1 6,750 people who were free of disease X were enrolled in a cohort study in 1985 and followed with annual exams and interviews through 1995. Exposure to factor A was determined at study enrollment and the participants were followed until 1995 to observe new cases of disease X. Data from the study at the end of follow-up are shown in the following table. What is the incidence rate of disease X among persons exposed to factor A?
.0%”>
Exposure to Factor A People with Disease X People without Disease X
Not Exposed
30
3,720
Exposed
120
2,880
.0%”>
.0%”>
.0%”>
Select one:
a. 0. 04
b. 0. 19
c. 0. 25
d. 4. 00
e. 5. 17
2. A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90% of cases an average of 6 months prior to symptom onset; however, the prognosis did not improve after diagnosis. Comparing the epidemiology of the disease prior to 2000 with the epidemiology of the disease after the development of the lab test, which statement is true concerning the disease in 2000?
Select one:
a. Incidence is higher and prevalence is higher than in 1999
b. Incidence is higher in 2000 but prevalence remains the same
c. Incidence is the same in 2000 but prevalence is higher than in 1999
d. Both incidence and prevalence remain the same as in 1999
e. Incidence is the same in 2000 but prevalence is lower than in 1999
3 A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90% of cases an average of 6 months prior to symptom onset; however, the prognosis did not improve after diagnosis. Which statement is true concerning the duration of the disease after the development of the lab test?
Select one:
a. Mean duration of a case of the disease is shorter in 2000
b. Mean duration of a case of the disease is the same in 2000
c. Mean duration of a case of the disease is longer in 2000
d. No inference about mean duration can be made since the lab test has only been available for 1 year
4. A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90% of cases an average of 6 months prior to symptom onset; however, the prognosis did not improve after diagnosis. Which statement is true concerning the disease-specific mortality rate after the development of the lab test?
Select one:
a. The mortality rate for the disease is decreased in 2000
b. The mortality rate for the disease is the same in 2000
c. The mortality rate for the disease is increased in 2000
d. No inference about the mortality rate can be made since the lab test has only been available for 1 year
5 A group of researchers are interested in conducting a clinical trial to determine whether a new cholesterol-lowering agent was useful in preventing coronary heart disease (CHD). They identified 14,327 potential participants for the trial. At the initial clinical exam, 422 were discovered to have CHD. The remaining subjects entered the trial and were divided equally into the treatment and placebo groups. Of those in the treatment group, 535 developed CHD after 5 years of follow-up while 568 developed CHD during the same period in the placebo group. What was the prevalence of CHD at the initial exam?
Select one:
a. 10. 4 per 1,000 persons
b. 18. 7 per 1,000 persons
c. 29. 5 per 1,000 persons
d. 47. 3 per 1,000 persons
e. 79. 3 per 1,000 persons
6. A group of researchers are interested in conducting a clinical trial to determine whether a new cholesterol-lowering agent was useful in preventing coronary heart disease (CHD). They identified 14,327 potential participants for the trial. At the initial clinical exam, 422 were discovered to have CHD. The remaining subjects entered the trial and were divided equally into the treatment and placebo groups. Of those in the treatment group, 535 developed CHD after 5 years of follow-up while 568 developed CHD during the same period in the placebo group. What was the incidence of CHD during the 5-year study?
Select one:
a. 10. 4 per 1,000 persons
b. 18. 7 per 1,000 persons
c. 29. 5 per 1,000 persons
d. 47. 3 per 1,000 persons
e. 79. 3 per 1,000 persons
7.
A multicenter double-blind randomized study was carried out to compare the effect of drug X with that of a placebo in patients surviving acute myocardial infarction (AMI). Treatment with the drug started 7 days after infarction in 1,884 patients, 52% of all persons who were evaluated for entry into the study. 945 participants were randomized to treatment with drug X while 939 were assigned to the placebo group. Patients were then followed for 12 months for reinfarction. There were 152 deaths in the placebo group and 98 in the group receiving drug X.
After entry into the study, patients were first classified into three groups, those who had a previous AMI, those with a first AMI who were at high risk for other cardiovascular diseases such as congestive heart failure, and those with a first AMI who were at low risk for other cardiovascular diseases. Which term best describes the study design?
Select one:
a. Cohort study
b. Randomized clinical trial with crossover design
c. Randomized clinical trial with factorial design
d. Randomized clinical trial with stratified randomization
e. Case study design
8.
A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study:
.0%”>
Had Blood Transfusion Did Not have Blood Transfusion Death Rate in Hospital
New Drug 43
41
0. 250
Existing drug 26
58
0. 083
Total 69
99
0. 167
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 31. 0%
b. 41. 1%
c. 51. 2%
d. 62. 3%
e. Incidence cannot be calculated with the information in this table
9. A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study:
What is the number of persons who died in hospital in the study?
.0%”>
Had Blood Transfusion Did Not have Blood Transfusion Death Rate in Hospital
New Drug 43
41
0. 250
Existing drug 26
58
0. 083
Total 69
99
0. 167
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 7
b. 17
c. 28
d. 35
e. The number of deaths cannot be calculated as the death rate has not been age-adjusted
10. A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment.
What is the main advantage of the randomization of the 168 study participants to one of the two drug treatment groups?
Select one:
a. Ensures that the researchers are masked to the treatment group assignment for each participant
b. Facilitates the age-adjustment of the death rate in each group
c. Reduces the potential for selection bias in allocation of treatment group
d. Ensures that the study groups are comparable for characteristics such as age and severity of condition prior to treatment assignment
e. Ensures that non-compliance will not affect the results
11. A prevalence survey conducted from January 1 through December 31, 2003 identified 380 new cases of tuberculosis in a city of 1,800,000 persons. The incidence rate of tuberculosis in this population has historically been 1 per 4,000 persons each year. What is the incident rate of tuberculosis per 100,000 persons in 2003?
Select one:
a. 10. 4 per 100,000 persons
b. 21. 1 per 100,000 persons
c. 25 per 100,000 persons
d. 47. 3 per 100,000 persons
e. 79. 3 per 100,000 persons
12. A prevalence survey conducted from January 1 through December 31, 2003 identified 380 new cases of tuberculosis in a city of 1,800,000 persons. The incidence rate of tuberculosis in this population has historically been 1 per 4,000 persons each year. Has the risk of tuberculosis increased or decreased during 2003?
Select one:
a. it has increased
b. it has decreased
c. it is impossible to determine
13. A prostate specific antigen (PSA) test is a quick screening test for prostate cancer. A researcher wants to evaluate it using two groups. Group A consists of 1,500 men who had biopsy-proven adenocarcinoma of the prostate while group B consists of 3,000 age- and race-matched men all of whom showed no cancer at biopsy. The results of the PSA screening test in each group is shown in the table.
What is the sensitivity of the screening test in the combined groups?
.0%”>
Group A Group B
Positive for PSA screening test 1,155
240
Total in Group 1,500
3,000
.0%”>
.0%”>
.0%”>
Select one:
a. 8 %
b. 20. 8%
c. 50%
d. 77%
e. 91%
14. A school nurse examined a population of 2,000 children in an attempt to detect nearsightedness. The prevalence of myopia in this population is known to be 25%. The sensitivity of the examination is 60% and its specificity is 80%. All children labeled as “positive” (i. e. , suspected of having myopia) by the school nurse are sent for examination by an optometrist. The sensitivity of the optometrist’s examination is 98% and its specificity is 90%. How many children are labeled “positive” by the school nurse?
Select one:
a. 400
b. 500
c. 600
d. 700
15. A study found that adults older than age 50 had a higher prevalence of pneumonia than those who were younger than age 50. Which of the following is consistent with this finding?
Select one:
a. Younger adults have a higher incidence of pneumonia
b. Older adults have a higher case-fatality rate from pneumonia
c. Younger adults with pneumonia are more likely to report being ill than older persons
d. Incidence rates do not vary by age, but older adults have pneumonia for a longer duration compared to younger adults
16. A survey was conducted among 1,000 randomly sampled adult males in the United States in 2005. The results from this survey are shown below. The researchers stated that there was a doubling of risk of hypertension in each age group younger than 60 years of age. You conclude that the researchers’ interpretation:
.0%”>
Age Group Percent of Person with Hypertension
18-29 years
5
30-39 years
10
40-49 years
20
50-59 years
40
60-69 years
60
70 and older
55
.0%”>
.0%”>
Select one:
a. Is correct
b. Is incorrect because prevalence rates are estimated
c. Is incorrect because it was based on proportions of the population sample
d. Is incorrect because incidence rates do not describe risk
e. Is incorrect because the calculations do not include adult females
17. Among those who are 25 years of age, those who have been driving less than 5 years had 13,700 motor vehicle accidents in 1 year, while those who had been driving for more than 5 years had 21,680 motor vehicle accidents during the same time period. It was concluded from these data that 25-year-olds with more driving experience have increased accidents compared to those who started driving later. This conclusion is:
Select one:
a. Correct based on the data
b. Incorrect because rates are not reported
c. Incorrect because prevalence estimates are given when incidence rates should be reported
d. Incorrect because there are no comparison groups identified
18. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. Calculate the attack rate among all students at the boarding school.
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 3. 9%
b. 4. 7%
c. 6. 7%
d. 9. 1%
e. 45%
19. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. Calculate the attack rates for boys.
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 3. 5%
b. 10. 5%
c. 24. 6%
d. 75. 4%
20. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. What is the proportion of total cases occurring in girls?
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 3. 3%
b. 4. 7%
c. 6. 7%
d. 10. 1%
e. 45%
21. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. What is the proportion of total cases occurring in students who live at home?
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 8. 8%
b. 91. 2%
c. 85. 5%
d. 10. 1%
e. 45%
22. For a disease such as liver cancer, which is highly fatal and of short duration, which of the following statements is true? Choose the best answer.
Select one:
a. Mortality rates will be much higher than incidence rates
b. Mortality rates will be much higher than prevalence rates
c. Incidence rates will be much higher than mortality rates
d. Case-fatality rates will be equal to mortality rates
e. Incidence rates will be equal to mortality rates
23. In 2002, investigators started a study of the association of cholesterol levels and stroke in a group of 2,000 healthy persons who had participated in a cholesterol screening program in 1992. The investigators determined exposure categories using cholesterol levels in all persons that were measured at the time of the screening program. A cutoff value of 200 mg/dL was used to define “high” cholesterol while those with levels below 200 were identified as having “low” cholesterol. Using this definition, 1,000 persons had “high” cholesterol levels while the remaining 1,000 persons had “low” cholesterol. The investigators determined that 150 cases of stroke occurred by the end of 2004, with 113 cases occurring in the high cholesterol group. What is the study design that the investigators used?
Select one:
a. Case-control study
b. Retrospective cohort study
c. Prospective cohort study
d. Cross-sectional study
e. Randomized clinical trial
24. In 2002, investigators started a study of the association of cholesterol levels and stroke in a group of 2,000 healthy persons who had participated in a cholesterol screening program in 1992. The investigators determined exposure categories using cholesterol levels in all persons that were measured at the time of the screening program. A cutoff value of 200 mg/dL was used to define “high” cholesterol while those with levels below 200 were identified as having “low” cholesterol. Using this definition, 1,000 persons had “high” cholesterol levels while the remaining 1,000 persons had “low” cholesterol. The investigators determined that 150 cases of stroke occurred by the end of 2004, with 113 cases occurring in the high cholesterol group. What type of risk measure should the investigators calculate?
Select one:
a. Odds ratio
b. Prevalence rate
c. Multiplicative interaction
d. Positive predictive value
e. Relative risk
25. In 2002, investigators started a study of the association of cholesterol levels and stroke in a group of 2,000 healthy persons who had participated in a cholesterol screening program in 1992. The investigators determined exposure categories using cholesterol levels in all persons that were measured at the time of the screening program. A cutoff value of 200 mg/dL was used to define “high” cholesterol while those with levels below 200 were identified as having “low” cholesterol. Using this definition, 1,000 persons had “high” cholesterol levels while the remaining 1,000 persons had “low” cholesterol. The investigators determined that 150 cases of stroke occurred by the end of 2004, with 113 cases occurring in the high cholesterol group. Using the reported study data, what is the estimate of the risk measure that was chosen?
Select one:
a. 3. 1
b. 3. 3
c. 67%
d. 1. 0
e. 0. 3
26. In a coastal area of a country in which a tsunami struck, there were 100,000 deaths in a population of 1. 4 million for the year ending December 31, 2005. What was the all-cause crude mortality rate per 1,000 persons during 2005?
Select one:
a. 10. 4 per 1,000 persons
b. 25. 7 per 1,000 persons
c. 41. 7 per 1,000 persons
d. 71. 4 per 1,000 persons
e. 79. 3 per 1,000 persons
27. In a study of the adverse effects of x-rays among children, a retrospective cohort study was done using records from several large children’s hospitals for the period of 1980 to 1985. 10,000 children were selected as a representative population of ill children seen at the hospitals during that time. Subjects were classified according to whether or not they received an x-ray during their stay in the hospital and were followed from their hospital stay through 2005 for the development of cancer. During the follow-up period, 49 incident cancers occurred in 3,263 children who had received an x-ray, and 47 incident cancers occurred in the 6,737 children who had not received an x-ray during their hospitalization. Which of the following issues should the investigators consider when interpreting whether a causal association exists between cancer incidence and childhood x-ray?
Select one:
a. Some study subjects were treated for cancer starting in 1980
b. Some study subjects had parents who were diagnosed with cancer
c. Some children received x-rays at other hospitals not included in this study
d. The children were different ages when they were admitted to the hospital
e. All of the above
28. Pandemic means that a disease:
Select one:
a. Occcurs clearly in excess of normal expectancy
b. Affects a large number of countries simultaneously
c. Is habitually present in human populations
d. Exhibit seasonal patterns
e. Is prevealent among animals
29. Test A has a sensitivity of 95% and a specificity of 90%. Test B has a sensitivity of 80% and a specificity of 98%. In a community of 10,000 people with 5% prevalence of the disease, Test A has always been given before Test B. What is the best reason for changing the order of the tests?
Select one:
a. The net sensitivity will be increased if Test B is given first
b. The total number of false positives found by both tests is decreased if Test B is given first
c. The net specificity will be decreased if Test B is given first
d. The total number of false negatives found by both tests is decreased if Test B is given first
e. There is no good reason to change the order of the tests
30. The incidence and prevalence rates of a chronic childhood illness for a specific community are given below. Based on the data, which of the following interpretations best describes disease X?
.0%”>
Incidence and Prevalence of Disease X in Children Aged 1 to 4 Years
Year Incidence Rate per 1,000 per Year Prevalence Rate per 1,000 per Year
1975
33. 2
23. 8
1985
38. 4
24. 7
1995
41. 8
24. 5
.0%”>
.0%”>
.0%”>
Select one:
a. The duration of disease is becoming shorter.
b. The duration of disease is becoming longer.
c. The case-fatality rate of this disease is decreasing.
d. Efforts to prevent new cases of this disease are becoming more successful.
e. The risk of the disease has decreased over the past 20 years.
31. The population of a city on February 15, 2005, was 36,600. The city has a passive surveillance system that collects hospital and private physician reports of influenza cases every month. During the period between January 1 and April 1, 2005, 2,200 new cases of influenza occurred in the city. Of these cases, 775 persons were ill with influenza according to surveillance reports on April 1, 2005. The monthly incidence rate of active cases of influenza for the 3-month period was:
Select one:
a. 4 per 1,000 population
b. 17 per 1,000 population
c. 20 per 1,000 population
d. 39 per 1,000 population
e. 130 per 1,000 population
32. The population of a city on February 15, 2005, was 36,600. The city has a passive surveillance system that collects hospital and private physician reports of influenza cases every month. During the period between January 1 and April 1, 2005, 2,200 new cases of influenza occurred in the city. Of these cases, 775 persons were ill with influenza according to surveillance reports on April 1, 2005. The prevalence rate of active influenza as of April 1, 2005, was:
Select one:
a. 4 per 1,000 population
b. 17 per 1,000 population
c. 20 per 1,000 population
d. 39 per 1,000 population
e. 130 per 1,000 population
33. The prevalence rate of a disease is two times greater in women than in men, but the incidence rates are the same in men and women. Which of the following statements may explain this situation?
Select one:
a. The duration of disease is shorter in women
b. Men are at greater risk for developing the disease
c. The case-fatality rate is lower for women
d. The age-adjusted mortality rate will be higher for women
e. The proportionate mortality rate for the disease is higher for men
34. The table below describes the number of illnesses and deaths caused by plague in four communities.
.0%”>
Total Deaths
Deaths from Plague
Sick from Plague
Community A
200
100
150
Community B
400
300
400
Community C
800
300
500
Community D
5000
500
650
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. Community A
b. Community B
c. Community C
d. Community D
35. This table represents the results of coronary magnetic resonance (CMR) angiography compared to x-ray angiography (the gold standard in diagnosis of coronary artery disease) in a high-risk population of patients scheduled to undergo x-ray angiography for suspected coronary artery disease. . Assuming that this sample of patients is representative of the general population, the sensitivity of the CMR test in the general population would be approximately:
.0%”>
Positive X-ray Negative X-ray
Positive CMR 56
25
Negative CMR 4
18
.0%”>
.0%”>
.0%”>
Select one:
a. Less than 75%
b. Between 75% and 85%
c. Between 85% and 90%
d. Between 90% and 95%
e. Greater than 95%
36. Two neurologists, Drs. J and K, independently examined 70 magnetic resonance images (MRIs) for evidence of brain tumors. As shown in the table below, the neurologists read each MRI as either “positive” or “negative” for brain tumors.
Based on the above information, the overall percent agreement between the two doctors including all observations is:
.0%”>
Dr. K Dr. J
Positive Negative
Positive 26
12
Negative 14
18
.0%”>
.0%”>
.0%”>
Select one:
a. 37. 1%
b. 62. 9%
c. 65. 0%
d. 68. 4%
e. 84. 6%
37. What is the diarrhea attack rate in persons who ate pizza but did not eat ice cream?
.0%”>
Ate Ice Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 39/52
b. 14/40
c. 14/70
d. 9/30
e. 23/70
38. What is the overall attack rate in persons who ate ice cream?
.0%”>
Ate Ice Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 30%
b. 33%
c. 35%
d. 58%
e. 75%
39. What was the probability of surviving the second year given survival to the end of the first year?
.0%”>
Year of Follow-up Number Alive at Start of Year Number of Death during Year
1
1,000
50
2
950
30
3
920
10
.0%”>
.0%”>
.0%”>
Select one:
a. Less than 75%
b. Between 75% and 85%
c. Between 85% and 90%
d. Between 90% and 95%
e. Greater than 95%
40. Which of the following are examples of a population prevalence rate?
Select one:
a. The number of ear infections suffered by 3-year-old children in March, 2006
b. The number of persons with hypertension per 100,000 population
c. The number of cases of skin cancer diagnosed in a dermatology clinic
d. b and c
e. All of the above
41. Which of the following best describes the retrospective design where subjects are sampled by disease status and is often used when the investigator is interested in rare diseases?
Select one:
a. intervention trial
b. case control study
c. retrospective cohort
d. ecologic study
e. none of the above
42. Which of the following best describes the study design that can be either retrospective or prospective and is often used when the investigators are interested in rare exposures.
Select one:
a. intervention trials
b. cohort studies
c. prevalence studies
d. case control study
e. none of the above
43. Which of the following improves the reliability of diabetes screening tests?
Select one:
a. Having the same lab analyze all samples
b. Taking more than one sample for each subject and averaging the results
c. Insuring that the instrument is standardized before each sample is analyzed
d. All of the above
44. Which of the following reasons can explain why a person who did not consume the infective food item got sick?
.0%”>
Ate Ice Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. They were directly exposed to persons who did eat the infective food item
b. Diarrhea is a general symptom consistent with a number of illnesses
c. There may have been an inaccurate recall of which foods were eaten
d. All of the above
e. None of the above
45. Which of the food items (or combination of items) is most likely to be the infective item(s)?
.0%”>
Ate I
Question
1 6,750 people who were free of disease X were enrolled in a cohort study in 1985 and followed with annual exams and interviews through 1995. Exposure to factor A was determined at study enrollment and the participants were followed until 1995 to observe new cases of disease X. Data from the study at the end of follow-up are shown in the following table. What is the incidence rate of disease X among persons exposed to factor A?
.0%”>
Exposure to Factor A People with Disease X People without Disease X
Not Exposed
30
3,720
Exposed
120
2,880
.0%”>
.0%”>
.0%”>
Select one:
a. 0. 04
b. 0. 19
c. 0. 25
d. 4. 00
e. 5. 17
2. A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90% of cases an average of 6 months prior to symptom onset; however, the prognosis did not improve after diagnosis. Comparing the epidemiology of the disease prior to 2000 with the epidemiology of the disease after the development of the lab test, which statement is true concerning the disease in 2000?
Select one:
a. Incidence is higher and prevalence is higher than in 1999
b. Incidence is higher in 2000 but prevalence remains the same
c. Incidence is the same in 2000 but prevalence is higher than in 1999
d. Both incidence and prevalence remain the same as in 1999
e. Incidence is the same in 2000 but prevalence is lower than in 1999
3 A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90% of cases an average of 6 months prior to symptom onset; however, the prognosis did not improve after diagnosis. Which statement is true concerning the duration of the disease after the development of the lab test?
Select one:
a. Mean duration of a case of the disease is shorter in 2000
b. Mean duration of a case of the disease is the same in 2000
c. Mean duration of a case of the disease is longer in 2000
d. No inference about mean duration can be made since the lab test has only been available for 1 year
4. A disease has an incidence of 10 per 1,000 persons per year, and 80% of those affected will die within 1 year. Prior to the year 2000, only 50% of cases of the disease were detected by physician diagnosis prior to death. In the year 2000, a lab test was developed that identified 90% of cases an average of 6 months prior to symptom onset; however, the prognosis did not improve after diagnosis. Which statement is true concerning the disease-specific mortality rate after the development of the lab test?
Select one:
a. The mortality rate for the disease is decreased in 2000
b. The mortality rate for the disease is the same in 2000
c. The mortality rate for the disease is increased in 2000
d. No inference about the mortality rate can be made since the lab test has only been available for 1 year
5 A group of researchers are interested in conducting a clinical trial to determine whether a new cholesterol-lowering agent was useful in preventing coronary heart disease (CHD). They identified 14,327 potential participants for the trial. At the initial clinical exam, 422 were discovered to have CHD. The remaining subjects entered the trial and were divided equally into the treatment and placebo groups. Of those in the treatment group, 535 developed CHD after 5 years of follow-up while 568 developed CHD during the same period in the placebo group. What was the prevalence of CHD at the initial exam?
Select one:
a. 10. 4 per 1,000 persons
b. 18. 7 per 1,000 persons
c. 29. 5 per 1,000 persons
d. 47. 3 per 1,000 persons
e. 79. 3 per 1,000 persons
6. A group of researchers are interested in conducting a clinical trial to determine whether a new cholesterol-lowering agent was useful in preventing coronary heart disease (CHD). They identified 14,327 potential participants for the trial. At the initial clinical exam, 422 were discovered to have CHD. The remaining subjects entered the trial and were divided equally into the treatment and placebo groups. Of those in the treatment group, 535 developed CHD after 5 years of follow-up while 568 developed CHD during the same period in the placebo group. What was the incidence of CHD during the 5-year study?
Select one:
a. 10. 4 per 1,000 persons
b. 18. 7 per 1,000 persons
c. 29. 5 per 1,000 persons
d. 47. 3 per 1,000 persons
e. 79. 3 per 1,000 persons
7.
A multicenter double-blind randomized study was carried out to compare the effect of drug X with that of a placebo in patients surviving acute myocardial infarction (AMI). Treatment with the drug started 7 days after infarction in 1,884 patients, 52% of all persons who were evaluated for entry into the study. 945 participants were randomized to treatment with drug X while 939 were assigned to the placebo group. Patients were then followed for 12 months for reinfarction. There were 152 deaths in the placebo group and 98 in the group receiving drug X.
After entry into the study, patients were first classified into three groups, those who had a previous AMI, those with a first AMI who were at high risk for other cardiovascular diseases such as congestive heart failure, and those with a first AMI who were at low risk for other cardiovascular diseases. Which term best describes the study design?
Select one:
a. Cohort study
b. Randomized clinical trial with crossover design
c. Randomized clinical trial with factorial design
d. Randomized clinical trial with stratified randomization
e. Case study design
8.
A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study:
.0%”>
Had Blood Transfusion Did Not have Blood Transfusion Death Rate in Hospital
New Drug 43
41
0. 250
Existing drug 26
58
0. 083
Total 69
99
0. 167
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 31. 0%
b. 41. 1%
c. 51. 2%
d. 62. 3%
e. Incidence cannot be calculated with the information in this table
9. A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study:
What is the number of persons who died in hospital in the study?
.0%”>
Had Blood Transfusion Did Not have Blood Transfusion Death Rate in Hospital
New Drug 43
41
0. 250
Existing drug 26
58
0. 083
Total 69
99
0. 167
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 7
b. 17
c. 28
d. 35
e. The number of deaths cannot be calculated as the death rate has not been age-adjusted
10. A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment.
What is the main advantage of the randomization of the 168 study participants to one of the two drug treatment groups?
Select one:
a. Ensures that the researchers are masked to the treatment group assignment for each participant
b. Facilitates the age-adjustment of the death rate in each group
c. Reduces the potential for selection bias in allocation of treatment group
d. Ensures that the study groups are comparable for characteristics such as age and severity of condition prior to treatment assignment
e. Ensures that non-compliance will not affect the results
11. A prevalence survey conducted from January 1 through December 31, 2003 identified 380 new cases of tuberculosis in a city of 1,800,000 persons. The incidence rate of tuberculosis in this population has historically been 1 per 4,000 persons each year. What is the incident rate of tuberculosis per 100,000 persons in 2003?
Select one:
a. 10. 4 per 100,000 persons
b. 21. 1 per 100,000 persons
c. 25 per 100,000 persons
d. 47. 3 per 100,000 persons
e. 79. 3 per 100,000 persons
12. A prevalence survey conducted from January 1 through December 31, 2003 identified 380 new cases of tuberculosis in a city of 1,800,000 persons. The incidence rate of tuberculosis in this population has historically been 1 per 4,000 persons each year. Has the risk of tuberculosis increased or decreased during 2003?
Select one:
a. it has increased
b. it has decreased
c. it is impossible to determine
13. A prostate specific antigen (PSA) test is a quick screening test for prostate cancer. A researcher wants to evaluate it using two groups. Group A consists of 1,500 men who had biopsy-proven adenocarcinoma of the prostate while group B consists of 3,000 age- and race-matched men all of whom showed no cancer at biopsy. The results of the PSA screening test in each group is shown in the table.
What is the sensitivity of the screening test in the combined groups?
.0%”>
Group A Group B
Positive for PSA screening test 1,155
240
Total in Group 1,500
3,000
.0%”>
.0%”>
.0%”>
Select one:
a. 8 %
b. 20. 8%
c. 50%
d. 77%
e. 91%
14. A school nurse examined a population of 2,000 children in an attempt to detect nearsightedness. The prevalence of myopia in this population is known to be 25%. The sensitivity of the examination is 60% and its specificity is 80%. All children labeled as “positive” (i. e. , suspected of having myopia) by the school nurse are sent for examination by an optometrist. The sensitivity of the optometrist’s examination is 98% and its specificity is 90%. How many children are labeled “positive” by the school nurse?
Select one:
a. 400
b. 500
c. 600
d. 700
15. A study found that adults older than age 50 had a higher prevalence of pneumonia than those who were younger than age 50. Which of the following is consistent with this finding?
Select one:
a. Younger adults have a higher incidence of pneumonia
b. Older adults have a higher case-fatality rate from pneumonia
c. Younger adults with pneumonia are more likely to report being ill than older persons
d. Incidence rates do not vary by age, but older adults have pneumonia for a longer duration compared to younger adults
16. A survey was conducted among 1,000 randomly sampled adult males in the United States in 2005. The results from this survey are shown below. The researchers stated that there was a doubling of risk of hypertension in each age group younger than 60 years of age. You conclude that the researchers’ interpretation:
.0%”>
Age Group Percent of Person with Hypertension
18-29 years
5
30-39 years
10
40-49 years
20
50-59 years
40
60-69 years
60
70 and older
55
.0%”>
.0%”>
Select one:
a. Is correct
b. Is incorrect because prevalence rates are estimated
c. Is incorrect because it was based on proportions of the population sample
d. Is incorrect because incidence rates do not describe risk
e. Is incorrect because the calculations do not include adult females
17. Among those who are 25 years of age, those who have been driving less than 5 years had 13,700 motor vehicle accidents in 1 year, while those who had been driving for more than 5 years had 21,680 motor vehicle accidents during the same time period. It was concluded from these data that 25-year-olds with more driving experience have increased accidents compared to those who started driving later. This conclusion is:
Select one:
a. Correct based on the data
b. Incorrect because rates are not reported
c. Incorrect because prevalence estimates are given when incidence rates should be reported
d. Incorrect because there are no comparison groups identified
18. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. Calculate the attack rate among all students at the boarding school.
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 3. 9%
b. 4. 7%
c. 6. 7%
d. 9. 1%
e. 45%
19. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. Calculate the attack rates for boys.
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 3. 5%
b. 10. 5%
c. 24. 6%
d. 75. 4%
20. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. What is the proportion of total cases occurring in girls?
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 3. 3%
b. 4. 7%
c. 6. 7%
d. 10. 1%
e. 45%
21. An outbreak of gastroenteritis occurred at a boarding school with a student enrollment of 846. Fifty-seven students reported symptoms including vomiting, diarrhea, nausea, and low-grade fever between 10 p. m. on September 24 and 8 p. m. on September 25. The ill students lived in dormitories that housed 723 of the students. The table below provides information on the number of students per type of residence and the number reporting illnesses consistent with the described symptoms and onset time. What is the proportion of total cases occurring in students who live at home?
.0%”>
Residence
Number of students
Number of cases
Boys Dormitory (all boys)
380
40
Girls Dormitory (all girls)
343
12
Day students (Live at home)
123 (46 boys, 77 girls)
5 (3 boys, 2 girls)
Total
846
57
.0%”>
.0%”>
.0%”>
Select one:
a. 8. 8%
b. 91. 2%
c. 85. 5%
d. 10. 1%
e. 45%
22. For a disease such as liver cancer, which is highly fatal and of short duration, which of the following statements is true? Choose the best answer.
Select one:
a. Mortality rates will be much higher than incidence rates
b. Mortality rates will be much higher than prevalence rates
c. Incidence rates will be much higher than mortality rates
d. Case-fatality rates will be equal to mortality rates
e. Incidence rates will be equal to mortality rates
23. In 2002, investigators started a study of the association of cholesterol levels and stroke in a group of 2,000 healthy persons who had participated in a cholesterol screening program in 1992. The investigators determined exposure categories using cholesterol levels in all persons that were measured at the time of the screening program. A cutoff value of 200 mg/dL was used to define “high” cholesterol while those with levels below 200 were identified as having “low” cholesterol. Using this definition, 1,000 persons had “high” cholesterol levels while the remaining 1,000 persons had “low” cholesterol. The investigators determined that 150 cases of stroke occurred by the end of 2004, with 113 cases occurring in the high cholesterol group. What is the study design that the investigators used?
Select one:
a. Case-control study
b. Retrospective cohort study
c. Prospective cohort study
d. Cross-sectional study
e. Randomized clinical trial
24. In 2002, investigators started a study of the association of cholesterol levels and stroke in a group of 2,000 healthy persons who had participated in a cholesterol screening program in 1992. The investigators determined exposure categories using cholesterol levels in all persons that were measured at the time of the screening program. A cutoff value of 200 mg/dL was used to define “high” cholesterol while those with levels below 200 were identified as having “low” cholesterol. Using this definition, 1,000 persons had “high” cholesterol levels while the remaining 1,000 persons had “low” cholesterol. The investigators determined that 150 cases of stroke occurred by the end of 2004, with 113 cases occurring in the high cholesterol group. What type of risk measure should the investigators calculate?
Select one:
a. Odds ratio
b. Prevalence rate
c. Multiplicative interaction
d. Positive predictive value
e. Relative risk
25. In 2002, investigators started a study of the association of cholesterol levels and stroke in a group of 2,000 healthy persons who had participated in a cholesterol screening program in 1992. The investigators determined exposure categories using cholesterol levels in all persons that were measured at the time of the screening program. A cutoff value of 200 mg/dL was used to define “high” cholesterol while those with levels below 200 were identified as having “low” cholesterol. Using this definition, 1,000 persons had “high” cholesterol levels while the remaining 1,000 persons had “low” cholesterol. The investigators determined that 150 cases of stroke occurred by the end of 2004, with 113 cases occurring in the high cholesterol group. Using the reported study data, what is the estimate of the risk measure that was chosen?
Select one:
a. 3. 1
b. 3. 3
c. 67%
d. 1. 0
e. 0. 3
26. In a coastal area of a country in which a tsunami struck, there were 100,000 deaths in a population of 1. 4 million for the year ending December 31, 2005. What was the all-cause crude mortality rate per 1,000 persons during 2005?
Select one:
a. 10. 4 per 1,000 persons
b. 25. 7 per 1,000 persons
c. 41. 7 per 1,000 persons
d. 71. 4 per 1,000 persons
e. 79. 3 per 1,000 persons
27. In a study of the adverse effects of x-rays among children, a retrospective cohort study was done using records from several large children’s hospitals for the period of 1980 to 1985. 10,000 children were selected as a representative population of ill children seen at the hospitals during that time. Subjects were classified according to whether or not they received an x-ray during their stay in the hospital and were followed from their hospital stay through 2005 for the development of cancer. During the follow-up period, 49 incident cancers occurred in 3,263 children who had received an x-ray, and 47 incident cancers occurred in the 6,737 children who had not received an x-ray during their hospitalization. Which of the following issues should the investigators consider when interpreting whether a causal association exists between cancer incidence and childhood x-ray?
Select one:
a. Some study subjects were treated for cancer starting in 1980
b. Some study subjects had parents who were diagnosed with cancer
c. Some children received x-rays at other hospitals not included in this study
d. The children were different ages when they were admitted to the hospital
e. All of the above
28. Pandemic means that a disease:
Select one:
a. Occcurs clearly in excess of normal expectancy
b. Affects a large number of countries simultaneously
c. Is habitually present in human populations
d. Exhibit seasonal patterns
e. Is prevealent among animals
29. Test A has a sensitivity of 95% and a specificity of 90%. Test B has a sensitivity of 80% and a specificity of 98%. In a community of 10,000 people with 5% prevalence of the disease, Test A has always been given before Test B. What is the best reason for changing the order of the tests?
Select one:
a. The net sensitivity will be increased if Test B is given first
b. The total number of false positives found by both tests is decreased if Test B is given first
c. The net specificity will be decreased if Test B is given first
d. The total number of false negatives found by both tests is decreased if Test B is given first
e. There is no good reason to change the order of the tests
30. The incidence and prevalence rates of a chronic childhood illness for a specific community are given below. Based on the data, which of the following interpretations best describes disease X?
.0%”>
Incidence and Prevalence of Disease X in Children Aged 1 to 4 Years
Year Incidence Rate per 1,000 per Year Prevalence Rate per 1,000 per Year
1975
33. 2
23. 8
1985
38. 4
24. 7
1995
41. 8
24. 5
.0%”>
.0%”>
.0%”>
Select one:
a. The duration of disease is becoming shorter.
b. The duration of disease is becoming longer.
c. The case-fatality rate of this disease is decreasing.
d. Efforts to prevent new cases of this disease are becoming more successful.
e. The risk of the disease has decreased over the past 20 years.
31. The population of a city on February 15, 2005, was 36,600. The city has a passive surveillance system that collects hospital and private physician reports of influenza cases every month. During the period between January 1 and April 1, 2005, 2,200 new cases of influenza occurred in the city. Of these cases, 775 persons were ill with influenza according to surveillance reports on April 1, 2005. The monthly incidence rate of active cases of influenza for the 3-month period was:
Select one:
a. 4 per 1,000 population
b. 17 per 1,000 population
c. 20 per 1,000 population
d. 39 per 1,000 population
e. 130 per 1,000 population
32. The population of a city on February 15, 2005, was 36,600. The city has a passive surveillance system that collects hospital and private physician reports of influenza cases every month. During the period between January 1 and April 1, 2005, 2,200 new cases of influenza occurred in the city. Of these cases, 775 persons were ill with influenza according to surveillance reports on April 1, 2005. The prevalence rate of active influenza as of April 1, 2005, was:
Select one:
a. 4 per 1,000 population
b. 17 per 1,000 population
c. 20 per 1,000 population
d. 39 per 1,000 population
e. 130 per 1,000 population
33. The prevalence rate of a disease is two times greater in women than in men, but the incidence rates are the same in men and women. Which of the following statements may explain this situation?
Select one:
a. The duration of disease is shorter in women
b. Men are at greater risk for developing the disease
c. The case-fatality rate is lower for women
d. The age-adjusted mortality rate will be higher for women
e. The proportionate mortality rate for the disease is higher for men
34. The table below describes the number of illnesses and deaths caused by plague in four communities.
.0%”>
Total Deaths
Deaths from Plague
Sick from Plague
Community A
200
100
150
Community B
400
300
400
Community C
800
300
500
Community D
5000
500
650
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. Community A
b. Community B
c. Community C
d. Community D
35. This table represents the results of coronary magnetic resonance (CMR) angiography compared to x-ray angiography (the gold standard in diagnosis of coronary artery disease) in a high-risk population of patients scheduled to undergo x-ray angiography for suspected coronary artery disease. . Assuming that this sample of patients is representative of the general population, the sensitivity of the CMR test in the general population would be approximately:
.0%”>
Positive X-ray Negative X-ray
Positive CMR 56
25
Negative CMR 4
18
.0%”>
.0%”>
.0%”>
Select one:
a. Less than 75%
b. Between 75% and 85%
c. Between 85% and 90%
d. Between 90% and 95%
e. Greater than 95%
36. Two neurologists, Drs. J and K, independently examined 70 magnetic resonance images (MRIs) for evidence of brain tumors. As shown in the table below, the neurologists read each MRI as either “positive” or “negative” for brain tumors.
Based on the above information, the overall percent agreement between the two doctors including all observations is:
.0%”>
Dr. K Dr. J
Positive Negative
Positive 26
12
Negative 14
18
.0%”>
.0%”>
.0%”>
Select one:
a. 37. 1%
b. 62. 9%
c. 65. 0%
d. 68. 4%
e. 84. 6%
37. What is the diarrhea attack rate in persons who ate pizza but did not eat ice cream?
.0%”>
Ate Ice Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 39/52
b. 14/40
c. 14/70
d. 9/30
e. 23/70
38. What is the overall attack rate in persons who ate ice cream?
.0%”>
Ate Ice Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. 30%
b. 33%
c. 35%
d. 58%
e. 75%
39. What was the probability of surviving the second year given survival to the end of the first year?
.0%”>
Year of Follow-up Number Alive at Start of Year Number of Death during Year
1
1,000
50
2
950
30
3
920
10
.0%”>
.0%”>
.0%”>
Select one:
a. Less than 75%
b. Between 75% and 85%
c. Between 85% and 90%
d. Between 90% and 95%
e. Greater than 95%
40. Which of the following are examples of a population prevalence rate?
Select one:
a. The number of ear infections suffered by 3-year-old children in March, 2006
b. The number of persons with hypertension per 100,000 population
c. The number of cases of skin cancer diagnosed in a dermatology clinic
d. b and c
e. All of the above
41. Which of the following best describes the retrospective design where subjects are sampled by disease status and is often used when the investigator is interested in rare diseases?
Select one:
a. intervention trial
b. case control study
c. retrospective cohort
d. ecologic study
e. none of the above
42. Which of the following best describes the study design that can be either retrospective or prospective and is often used when the investigators are interested in rare exposures.
Select one:
a. intervention trials
b. cohort studies
c. prevalence studies
d. case control study
e. none of the above
43. Which of the following improves the reliability of diabetes screening tests?
Select one:
a. Having the same lab analyze all samples
b. Taking more than one sample for each subject and averaging the results
c. Insuring that the instrument is standardized before each sample is analyzed
d. All of the above
44. Which of the following reasons can explain why a person who did not consume the infective food item got sick?
.0%”>
Ate Ice Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. They were directly exposed to persons who did eat the infective food item
b. Diarrhea is a general symptom consistent with a number of illnesses
c. There may have been an inaccurate recall of which foods were eaten
d. All of the above
e. None of the above
45. Which of the food items (or combination of items) is most likely to be the infective item(s)?
.0%”>
Ate Ice Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. Pizza only
b. Ice cream only
c. Neither pizza nor ice cream
d. Both pizza and ice cream
e. Cannot be assumed from the data shown
ce Cream
Did not eat ice Cream
Diarrhea
Total
Diarrhea
Total
Ate Pizza
39
52
14
40
Did not eat Pizza
11
15
9
30
.0%”>
.0%”>
.0%”>
.0%”>
.0%”>
Select one:
a. Pizza only
b. Ice cream only
c. Neither pizza nor ice cream
d. Both pizza and ice cream
e. Cannot be assumed from the data shown
