A weight-loss guru is offering free exercise training and diet plans for people who want to participate in her program.She finds that 85 percent of the participants who signed up lost an average of 30 pounds in just six months.She then promotes her program as the most effective plan available and promises each participant a weight loss of 20 pounds or more.Is her plan really as effective as she says?
A) Yes; the study included both diet and exercise as part of the plan.
B) Yes; the estimated weight loss is a conservative estimate (20 pounds) compared to the mean weight loss for the study (30 pounds).
C) No; the study should include both men and women.
D) No; the study is based on a volunteer sample, which may be very different from a randomly selected one.

Question

Quizplus · Accepted Answer

The study is based on a volunteer sample, which may be very different from a randomly selected one. Therefore, the results cannot be generalized to the larger population. Additionally, the fact that the study only included participants who signed up for the program may introduce a bias towards individuals who are more motivated or have more disposable income to spend on weight-loss programs.

A Weight-Loss Guru Is Offering Free Exercise Training and Diet