Twenty-five patients at a large clinic volunteer to participate in a study focusing on weight loss. These 25 patients had a mean weight loss score of x̄= 4500 g over two weeks. Suppose we know that the standard deviation of the population of weight changes on this particular diet is σ= 100 g. The results of the study were widely critiqued. How could the researchers have improved the quality of their research?

Question

Quizplus · Accepted Answer

Using a volunteer sample can introduce bias into the study, as those who volunteer may not be representative of the larger population. To improve the quality of the study, the researchers could have used a random sample of participants instead. Running the study for a longer duration or sampling fewer people would not necessarily address the issue of bias in the sample.

Twenty-Five Patients at a Large Clinic Volunteer to Participate in a Study