Gerard conducts a study to examine the effectiveness of an exercise program on obese people. the participants must exercise for one hour every day for six months. by the end of the fourth month, gerard finds that 75 percent of the participants dropped out of the study. what kind of problem has gerard encountered in his study?

Attrition

Explanation:

Attrition: The term attrition refers to the process of a group getting smaller in number because members of the group are dropping out. Due to dropping out of the member of a group for different reasons in a research study, the reliability is being threatened.

In other words, if cases of a research study are getting lost over time then it will lead to attrition.

Key feature: Progressive loss of data in a research study or the wearing away.

The kind of problem Gerard has encountered in his study is attrition.

answer:

d. because dr. laguardia selected a widely used measure, his study generalizes to has strong external validity. external validity has limited external validity. other applications of this measure.

the widely used measure that he applied to his experiment was the benton facial recognition test. it employed on to football players and as result, only players who suffered brain concussions did not pas this test. and although it has an external validity, it is limited because it isn't general to apply to other population.