Dr.Krenshaw believes that people who are under stress will develop more colds than people who are not under stress.When he randomly selects 20 participants and exposes them to high levels of stress, he finds that 17 of the participants develop colds.Based on these results, Dr.Krenshaw concludes that stress causes an increase in the number of colds a person experiences.His reasoning may be flawed because in this study:

Question

Quizplus · Accepted Answer

Without a control group for comparison, Dr. Krenshaw cannot determine if the high rate of colds among his participants is due to the stress they experienced or to other factors. The lack of a control group is a major flaw in this study design.

DrKrenshaw Believes That People Who Are Under Stress Will Develop