Which of the following is true about the P value?


Indicates the probability of seeing the observed result, and results more extreme, by chance alone (given that the null hypothesis is true)

Indicates the probability that the null hypothesis is true

Rules out the role of bias and/or confounding

Indicates that the results observed are of medical or public health significance

Question 32

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


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

The observed results may be true

The observed results may be due to bias

The observed results may be due to confounding

All of the above

Question 33

Which of the following statements is/are true about the 95% confidence interval?


If you did the study 100 times and got 100 point estimates and 100 confidence intervals, in 95 of the 100 results, the true point estimate would lie within the given interval.

The range within which the true measure of effect lies with a stated probability, or a certain degree of assurance (95%).

The confidence interval is calculated around the point estimate and quantifies the variability around the point estimate.

The 1st and 2nd answers only

All of the above

Question 34

Compensating research participants is a necessary part of the research protocol, ensures participation, and enhances the quality of the data collected.




Question 35

A cohort study of liver cancer among alcoholics was conducted. Incidence rates of liver cancer among alcoholic men are compared to a group of non-alcoholic men. Gender is a confounder in this study.




Question 36

Which of the following should be included in an informed consent process?


An explanation of the research study

A statement that a participant may withdraw at any time from the study

An acknowledgement of possible risks to the participant

Information on whom to contact for answers to questions about the research

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

All of the above

Question 37

A study of the risk of pulmonary hypertension among women who take diet drugs to lose weight was undertaken. The crude relative risk of pulmonary hypertension comparing diet drug users to nonusers is 17.0, and the age-adjusted relative risk is 5.0. Age is a confounder in this study.




Question 38

Town A and Town B are both located in Massachusetts. Both towns have approximately 100,000 residents, and their own water supply. Fluoride is added to the water supply of Town A; nothing is added to the water supply of Town B. The decision to add fluoride to Town A’s water, and not Town B’s, was made using a random number table. Both towns are monitored and compared with regards to the occurrence of new cases of dental caries (cavities) over a 5 year period. What type of study is this?


Individual Preventive Randomized Controlled Trial

Community Preventive Randomized Controlled Trial

Individual Therapeutic Randomized Controlled Trial

Community Therapeutic Randomized Controlled Trial

Question 39

Subjects with a confirmed diagnosis of carpal tunnel syndrome were compared to a comparable group without carpal tunnel syndrome and both groups were asked about their prior occupational and recreational exposures, including hours per week of computer use. This is an example of which study design?


Case-control study

Prospective cohort study

Retrospective Cohort Study

Cross-sectional study