In a study to examine the relationship between alcohol use and Alzheimer’s disease, 500 participants aged 60 and older who have been diagnosed with Alzheimer’s disease were selected for this study. The 500 participants were classified into three groups by alcohol use with one group consisting of participants who do not use alcohol, a second group consisted of participants with low or moderate alcohol use, and a third group consisted of participants with high alcohol use. Doctors will use a cognitive test to assess the stage of a participant’s Alzheimer’s disease and comparisons are to be made among the three groups.

(a) What is the target population in this study?

(b) What are the units of the target population?

(c) What is the sample size for this study?

(d) Is this an experiment or an observational study?

(e) What are the treatment groups in this study?

(f) Was randomization used to create the three groups of participants?