Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

A study is designed to investigate potential adverse effects of drug X. A table

ID: 2921559 • Letter: A

Question

A study is designed to investigate potential adverse effects of drug X. A table given below summarizes the outcomes. The researcher randomly assigns 204 from a group of 409 participants to take drug X. The remaining 205 subjects received placebo. Row 1 of the data table gives the numbers of participants who report experiencing adverse effects. Another variable we consider is age.

One argues that age here is a stratifying variable. Do you agree with this argument? Why or why not?

Drug X Placebo Age < 55 Age 55+ Age < 55 Age 55+ Adverse 8 22 5 16 No Effect 98 76 115 69

Explanation / Answer

A stratifying variable is one which divides a population sample into strata or groups in order to select a stratified sample. Age variable in this case divides the sample into less than 55 yrs category and 55 plus category. Thus, Age is a stratifying variable in this case.