Chapter 9.3, Problem 9.45E

To determine

To explain bias in the results of the study.

Answer to Problem 9.45E

The non-response bias occurs in the study.

Explanation of Solution

First need to know about the non-response bias. It is occurred when the results of not having data for everybody in the sample.

The 59 people who dropped out will create nonresponse bias, because they might have had a common reason for dropping out, such as not having lost any weight yet. Then the actual weight loss would have been a lot less and thus the treatment would appear to be a lot less effective when we add data about the 59 dropouts.