Without using appropriate experimental and control groups,extraneous events in subjects' lives can make history a threat to internal validity,even if those events are of no historical importance to people in general.

Question

Quizplus · Accepted Answer

Without appropriate experimental and control groups, it is difficult to isolate the effects of the independent variable from other external factors, such as extraneous events in subjects' lives. These events can create confounding variables, which undermine the internal validity of the study by making it unclear whether the observed changes are due to the independent variable or some other factor. Even if these events are not historically significant, they can still have an impact on the results of the study, which is why it is important to control for them through proper experimental design.

Without Using Appropriate Experimental and Control Groups,extraneous Events in Subjects