For a hypothesis test evaluating the effect of a treatment on a population mean,what basic assumption is made concerning the treatment effect?
A)If there is a treatment effect, it will increase the scores.
B)If there is a treatment effect, it will decrease the scores.
C)If there is a treatment effect, it will add (or subtract) a constant to each score.
D)If there is a treatment effect, it will multiply (or divide) each score by a constant.

Question

Quizplus · Accepted Answer

The basic assumption made in a hypothesis test evaluating the effect of a treatment on a population mean is that if there is a treatment effect, it will add (or subtract) a constant to each score. This means that the treatment effect will shift the distribution either to the right or to the left, but it will not change the shape of the distribution or its spread. This assumption is usually expressed as equal variances in the two groups being compared. Therefore, the appropriate choice is C.

For a Hypothesis Test Evaluating the Effect of a Treatment