Final answer:
The experimental units or subjects in a pharmaceutical study are the men and women who took the drug or placebo. These individuals are the focus of the research to measure the effect of the treatment, distinguishing them from the researchers or the treatments themselves. Option b.
Step-by-step explanation:
The experimental units or subjects in the described study are the men and women who took the drug or placebo. These individuals are the entities to which the treatments (the new drug and placebo) are applied, and their responses to the treatments are measured at the end of the study period. This is because experimental units are the smallest subdivision of the experimental material to which treatments are applied independently to and measurements are observed and/or recorded for. The experimental units are not the drug and the placebo (which are treatments), the researchers (who are conducting the study), or all men and women in their 50's (which represents the entire population from which the sample is drawn).
Randomized control trials (RCTs) like this one are used to test the efficacy of a new treatment or intervention. Both the control group and the experimental group are assessed to determine whether there is a statistically significant effect from the treatment. To minimize bias and the influence of participants' and researchers' expectations on the outcomes—known as the placebo effect—a double-blind design is typically used where neither group knows if they are receiving the active drug or a placebo.
Therefore, the correct answer to the question is B) The men and women who took the drug or placebo.