epiquiz!!!!!!!!!!!!

27 Jun epiquiz!!!!!!!!!!!!

Question
Question 1

. ? Selection bias is most likely to occur in which type of study????Answer

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. Prospective cohort studies

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. Retrospective cohort studies

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. Case-control studies

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. Both retrospective cohort and case-control studies

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2 points

Question 2

. ? A case-control study is being conducted where 10% of the cases and controls actually had the exposure of interest. However, when asked about the exposure, only 7% of each group recalled the exposure correctly. This inaccuracy, represented equally between cases and controls, could be called:???Answer

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. Differential misclassification bias

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. Nondifferential misclassification bias

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. Surveillance bias

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. Selection bias

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2 points

Question 3

. ? When assessing the results of a study, what are the possible explanations for the observed results????Answer

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. The observed results may be due to chance (i.e., random error)

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. The observed results may be true

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. The observed results may be due to bias

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. The observed results may be due to confounding

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. The 3rd and 4th answers only

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. The 1st, 3rd, and 4th answers only

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. All of the above

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2 points

Question 4

. ? If a study fails to detect a significant difference between treatment A and treatment B when in fact the treatments do differ, the following type of error has occurred.???Answer

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. Type I error

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. Type II error

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. Treatment discrimination error

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. Difference testing error

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2 points

Question 5

. ? Controls are needed in a case-control study to evaluate whether the frequency of a factor or past exposure among the cases is different from that among comparable persons who do not have the disease under investigation.???Answer?True ?False ??

2 points

Question 6

. ? Controlled clinical trials enable researchers to:???Answer

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. Derive knowledge about the origins of a disease

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. Control the level of exposure to a treatment

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. More accurately identify cause and effect

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. All of the above

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2 points

Question 7

. ? A case-control study was conducted to identify risk factors for the common cold. Living with children under the age of 10 was one of the risk factors evaluated. The odds ratio for this association was 9.0, and the 95% confidence interval ranged from 1.2 to 85. Which of the following statements is true about this association????Answer

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. People who lived with a child under the age of 10 had 9 times the risk of getting a cold compared to people who did not live with children under the age of 10.

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. The P value was greater than 0.05.

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. The P value was less than 0.05.

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. The association was statistically significant.

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. The true strength of association could be estimated more precisely if the study were repeated with a larger sample.

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. The 1st and 2nd answers only

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. The 1st and 3rd answers only

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. The 1st, 3rd, 4th, and 5th answers only

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. The 1st, 2nd, and 5th answers only

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2 points

Question 8

. ? What sources can be used to identify controls for a case-control study????Answer

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. General population

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. Hospital/clinic patients

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. Friends and relatives

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. All of the above

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2 points

Question 9

. ? When assessing a positive relationship between alcohol consumption and oral cancer using a case-control study, increasing the sample size of the study will result in which of the following????Answer

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. A lower P value

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. A greater odds ratio

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. A smaller 95% confidence interval

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. A higher disease prevalence

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. The 1st and 3rd answers only

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. The 2nd and 4th answers only

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. The 1st, 2nd, and 3rd answers only

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. All of the above

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. None of the above

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2 points

Question 10

. ? A southwestern state passed a law in 1988 making it illegal to drive without wearing a seat belt. To determine whether the law had made a difference in terms of mortality, a researcher in the state health department compiled data on deaths due to vehicle crashes in the 5 years before 1988 and in the 5 years after 1988. What type of study is this????Answer

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. Randomized controlled trial

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. Concurrent cohort study

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. Retrospective cohort study

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. Case-control study

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. Nested case-control study

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. Cross-sectional study

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. Ecologic study

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2 points

Question 11

. ? Any systematic error in the design or conduct of a study that results in an incorrect estimate of an exposure’s effect on the risk of disease is called:???Answer

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. Confounding

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. Bias

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. Stratification

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. Effect modification

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2 points

Question 12

. ? For a variable to be a confounder, it must be:???Answer

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. Associated with the disease (outcome) under study

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. Associated with the risk factor (exposure) under study

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. Both of the above

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. Neither of the above

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2 points

Question 13

. ? Which one of the following statements best describes a limitation of cross-sectional studies????Answer

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. No information on individuals

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. Unclear temporal relationship between exposure and disease

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. No comparison group

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2 points

Question 14

. ? The primary difference between an experimental and observational study is:???Answer

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. The investigator is “blinded” (prevented from knowing the subjects’ true exposure status until the end of the study) in an experimental study but not in an observational study.

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. The investigator controls the subject’s exposure in an experimental study but not in an observational study.

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. The investigator controls the subject’s outcome in an experimental study but not in an observational study.

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. Experimental studies are conducted with animals; observational studies are conducted with humans.

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2 points

Question 15

. ? Over the past 2 years, efforts were made to identify and determine the mortality and morbidity experience of several thousand military personnel who were stationed in the Persian Gulf and elsewhere in Europe in 1991. What type of study is this????Answer

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. Case-control study

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. Prospective cohort study

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. Retrospective cohort study

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. Randomized trial

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2 points

Question 16

. ? A cross-sectional study of the relationship between blood type and the risk of cataracts will produce misleading results because you cannot tell the correct temporal relationship between the exposure (blood type) and disease (cataracts).???Answer?True ?False ??

2 points

Question 17

. ? Researchers collected baseline information on oral contraceptive use from a group of female college seniors from a large university. Each year for the next 20 years, the women were followed up on to determine whether or not the participants had developed any of several conditions. What type of study is this????Answer

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. Case-control study

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. Prospective cohort study

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. Retrospective cohort study

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. Randomized trial

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. Cross-sectional study

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2 points

Question 18

. ? The healthy worker effect is a form of what type of bias????Answer

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. Selection bias

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. Control-selection bias

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. Interviewer/recording bias

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. Surveillance, diagnostic, or referral bias

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2 points

Question 19

. ? When chance, bias, and confounding have been ruled out as alternative explanations for an association, we may conclude that the association is causal.???Answer?True ?False ??

2 points

Question 20

. ? Advantages of a case-control design include all the following except:???Answer

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. It is appropriate for studying rare diseases.

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. It is appropriate for studying rare exposures.

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. The odds ratio can provide an estimate of the relative risk.

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. Multiple exposures can be studied.