Multiple Choice Question

uestion 31 (1 point) The following are survival times (in months) recorded for six tumor-bearing rats being observed after radiation therapy:  1.4 1.7 2.3 2.5 3.2 3.8   If the observed value of 3.8 months is mistakenly recorded as 38 months, what will be the effect on statistics for this study? Question 31 options: An increase in the median An increase in the mode An increase in the mean An increase in both the median and the mean An increase in the median, the mode, and the mean Question 32 (1 point) The following data represent the length of hospitalization (in weeks) for five patients with total hip replacement who receive no physical therapy during their stay:  4 4 3 5 4 20   What is the best measure of central tendency for this set of data? Question 32 options: Mean Variance Mode Median Standard deviation Question 33 (1 point) The standard error of the mean is used for which of the following functions?  Question 33 options: To describe the subject-to-subject variation in values of the response variable. To describe the precision with which the sample mean estimates the unknown population mean. To measure the average distance between a measurement and the population mean. To calculate the normal range of clinical values for a diagnostic test. None of the above Information The following tabulation presents the mean cumulative weight loss in grams for 12 patients receiving propranolol and for 11 control patients following sweating during insulin-induced hypoglycemia.     n Mean Weight Loss (in grams)   Standard Deviation Propranolol 12 120 10.0 Control 11 70 8.0   Do the data present sufficient evidence to conclude that the mean cumulative weight loss is different in the two groups? (Use a = 0.05). Question 34 (1 point) What is the appropriate statistical test to use for this study?  Question 34 options: one-sample t-test paired t-test two-sample t-test two-sample z-test Question 35 (1 point) What are the correct null and alternative hypotheses for this study?  Question 35 options: H0: μPropanolol = μControl; HA: μPropanolol > μControl H0: μPropanolol = μControl; HA: μPropanolol ≠ μControl H0: μPropanolol = μControl; HA: μPropanolol [removed] 100 Question 36 (1 point) What is the decision rule for this statistical test under the null hypothesis?  Question 36 options: If |t| > t23df, α/2 = 1.714, then reject the null hypothesis. If |t| > t22df, α/2 = 2.074, then reject the null hypothesis. If |t| > t21df, α/2 = 2.080, then reject the null hypothesis. If |t| > t11df, α/2 = 1.796, then reject the null hypothesis. Question 37 (1 point) Compute the test statistic, assuming a pooled estimate of the variance is 82.86.  Question 37 options: t = 3.80 t = 13.16 t = 14.42 t = 19.01 Question 38 (1 point) What is your statistical decision?  Question 38 options: Fail to reject the null hypothesis and conclude that there is no difference in the means. Fail to reject the null hypothesis and conclude that the mean in the Propanolol group is greater than the mean in the control group. Reject the null hypothesis and conclude that the mean in the Propanolol group is greater than 100g. Reject the null hypothesis and conclude that the two means are different. Question 39 (1 point) Calculate the 95% confidence interval for the true difference in the mean cumulative weight loss for the two groups.  Question 39 options: (47.9, 52.1) (42.1, 57.9) (46.2, 53.8) (112.1, 127.9) Question 40 (1 point) Which of the following is true for a disease which has a short duration and is highly fatal?  Question 40 options: Incidence rates will be similar to mortality rates.  Incidence rates will not be related to mortality rates.  Mortality rates will be much higher than incidence rates.  Incidence rates will be much higher than mortality rates.  Question 41 (1 point) Read the statement carefully and then answer the following question. “The NAAT test used to screen for Chlamydia detects as many as 91 percent of infections in women.” Sensitivity of the screening test for Chlamydia in women is 91%. True or false?  Question 41 options: True False Question 42 (1 point) Read the statement carefully and then answer the following question. “The NAAT test used to screen for Chlamydia detects as many as 91 percent of infections in women.” Proportion of false negatives is 9%. True or false?  Question 42 options: True False Question 43 (1 point) 1. People with high levels of plasma high-density lipoprotein (HDL) cholesterol have been found to be at low risk for coronary heart disease. Factors associated with plasma HDL cholesterol were sought in a study of 293 healthy men. The table shows the correlation coefficient and the p-value associated with a correlation analysis between plasma HDL cholesterol and each of the variables listed. All measurements were taken at the sametime for each of the 293 participants. Which of the following statements can be made regarding plasma triglyceride levels? (2.0 points)     r p-value Plasma triglyceride -0.42 <0.001 Alcohol intake 0.24 <0.001 Serum glucose -0.19 [removed]0.05 Diastolic blood pressure -0.04 >0.05 Question 43 options: By increasing someone’s plasma triglyceride levels, we can increase his plasma HDL cholesterol level. By reducing someone’s plasma triglyceride levels, we can increase his plasma HDL cholesterol level. High levels of plasma HDL cholesterol tend to be found in men with low plasma triglyceride levels. Low levels of plasma HDL cholesterol tend to be found in men with low plasma triglyceride levels. The p-value is too small to regard the correlation as anything other than a chance occurrence. Question 44 (1 point) 1. A study of 883 pregnancies was used to obtain a multiple linear regression equation relating the gestation in weeks to maternal characteristics.   Independent Variable Slope Coefficient (β) Age (years) -0.0215 Height (inches) 0.0279 Education (years) 0.0424 Race (white=0, black=1) -1.1600 Number of previous pregnancies 0.0103     Intercept=37.9     The intercept indicates:  Question 44 options: The mean gestation for this series of pregnancies The earliest termination of pregnancy for this series The latest termination of pregnancy for this series The predicted gestation when all the independent variables have values of zero The strength of the association between gestation and the five independent variables Question 45 (1 point) An investigator is interested in the association between a family living near a major highway and a child’s diagnosis of autism. To study this relationship, she selected 200 children who were diagnosed with autism and 200 children born in the same time period and in the same hospital who did not have a diagnosis of autism. She then contacted the families for information regarding their place of residence at the child’s birth. This is an example of:  Question 45 options: Cross-sectional study Retrospective cohort study Case-control study Community trial Question 46 (1 point) Which statement best describes the major advantage of experimental studies? Question 46 options: It avoids observer bias.  Design is rigorous, so it is more ethical.  It is easy to replicate results in other subjects.  It rules out self-selection of participants to different treatment groups.  It enrolls representative patients.  Question 47 (1 point) A report of a clinical trial of a new drug versus a placebo noted that the new drug gave a higher proportion of success than did the placebo. Accompanying this finding was the statement chi-square test statistic = 4.72, with a p<0.05. In light of this information, we may conclude: Question 47 options: Fewer than 1 in 20 will fail to benefit more from the drug than the placebo.  Fewer than 1 in 20 patients will benefit more from the placebo than the drug.  The probability of treatment success is less than 5% for a patient given the drug.  If the drug were effective, the probability of the reported finding is less than 5%.  If the drug were ineffective, the probability of the reported finding is less than 5%.  Question 48 (1 point) In a cross-sectional survey of 1000 people, 500 people were found to have disease ‘y’ and 500 did not have disease ‘y’. With regard to a suspected etiologic factor, 400 of the cases had exposure ‘x’ and only 100 of the controls had exposure ‘x’. The risk (or incidence) of the disease in people with the factor is:  Question 48 options: 80% 40% 16% 20% Should not be computed from data given Question 49 (1 point) The 95% confidence interval for the mean is approximately equal to the sample mean plus and minus two times the standard error of the mean.  Question 49 options: True False Question 50 (1 point) Sample size calculations should only be done after the study has ended in order to ensure accuracy.  Question 50 options: True False