16. When gathering a sample for your study, you selectedsubjects in the general population and categorized them as smokersand non-smokers. Which type of sample do you have?
A. random sample
B. stratified random sample
C. cluster sample
D. none of these
17. You are entering your work cafeteria and are approached byan individual to participate in their study by answering a fewquestions. As a subject for this study, you were selected by whichmethod of sampling?
A. Convenience sampling
B. Random sampling
C. Purposive sampling
D. Snowball sampling
18. You want to obtain a sample of individuals who have stage 1breast cancer and are in the age group of 40-65 years. Which of thefollowing sampling methods will be the most appropriate?
A. Convenience
B. Purposive
C. Snowball
D. Simple random sampling
19. A randomized clinical trial is designed to study theefficacy of medication “X” to treat attention deficit disorder inindividuals. Researchers are interested to make comparisons amongdifferent age groups. An initial pool of 1000 subjects (takingmedication X) was selected. These subjects were then grouped by age(6-10 yr olds, n=300; 10- 14 yr olds, n= 400; and 14- 18 yr old, n=300). A random sample of n= 300 was selected as study participantsfrom the three age groups to represent the original distribution ofthese age groups in the N=1000 individuals. Please identify thetype of sampling used in this study.
A. Systematic random sampling
B. Stratified random sampling
C. Simple random sampling
20.In case-crossover studies, all fixed individualcharacteristics that might confound the association of interest arecontrolled for.
A. True
B. False
C.Neither
