George Washington UniversityPUBH 6003

1)Researchers began a study in 1960 with a group of 5,500 healthy adults living in the Midwest. At that time they asked all study participants about their eating habits. All new cases of coronary heart disease were recorded in this group between 1960-1995. This is an example of a:

Select one:

1. Case-control study
2. Cross-sectional study

3. Clinical trial
4. Retrospective cohort study

e. Prospective cohort study

Question 2

Which of the following statements describes a major advantage of randomly assigning study participants to the different treatment groups in a clinical trial (ie randomization)?

Select one:

a. It prevents information bias

b. It minimizes confounding

3. It minimizes effect modification

4. It eliminates all ethical issues
5. It is most efficacious

Question 3

All of the following statements are generally true of prospective cohorts studies EXCEPT:

Select one:

a. They are useful for studying the effects of rare exposures

b. They are an effective way to study diseases with long latency periods

3. Selection bias is rarely an issue

4. The study groups may consist of exposed and unexposed cohort members

5. They provide good measures of incidence

Question 4

Among elderly subjects who are fit, vigorous exercise reduces the risk of heart disease which would lead to a reduction in such things as myocardial infarctions. However, among elderly subjects who are unfit, the initiation of vigorous exercise might precipitate a myocardial infarction (i.e. heart attack). Fitness may be considered:

Select one:

a. A risk factor

b. An effect modifier

3. A confounder

4. A necessary cause
5. A sufficient cause

Question 5

Cases and controls were enrolled into a study of end-stage renal disease. Participants were interviewed about their lifetime consumption of Ibuprofin and other medications. All participants tended to have difficulty correctly estimating their lifetime medication use, and cases and controls provide about the same quality of data. This situation would lead to:

Select one:

1. selection bias
2. differential information bias

 c. non-differential information bias

d. confounding

e. no bias

Question 6

The scenario described in question 7 would most likely lead to

Select one:

 a. Bias towards the null

2. Bias away from the null
3. A very small bias