You conduct a study that examines the role of exercise on depression alleviation.You assign the first 50 people who are motivated to sign up to the experimental group,and the second group of 50 people,who sign up much later,to the control group.After one month,you find that the experimental group (who exercised three times a week on average)is significantly less depressed than the control group (who exercised one time a week on average).Although you may be tempted to conclude that exercise helps stave off depression,you cannot because of a lack of ____ in your study.

Question

Quizplus · Accepted Answer

The key issue in this study is that the groups were not randomly assigned, which means there may have been some pre-existing differences in the individuals who signed up earlier versus later that could have affected the outcome. Random assignment is important to ensure that any differences between groups are due to the treatment (in this case, exercise) and not due to other factors. Random sampling and surveying are not directly relevant, and objectivity is important but not specifically lacking in this scenario.

You Conduct a Study That Examines the Role of Exercise