In which of the following situations should an a priori contrast be used?
A) A t-test is used to conclude that men consume more hamburgers than women
B) A chi-square test is used to conclude that there is a difference in type of living quarters by class status
C) Using a one-way ANOVA, significant differences in ad recall are found between three experimental groups and one control group
D) A Z test indicates that the national average of the number of soft drinks consumed in the US exceeds that of France
E) All of the above should use an a priori contrast

Question

Quizplus · Accepted Answer

A priori contrast is used in situations where there are specific hypotheses about the direction of differences or relationships between groups or variables. In option C, there are already three experimental groups and a control group, which suggests that there are specific hypotheses about the differences between the groups. Options A, B, and D do not mention any specific hypotheses about the direction of differences, hence, an a priori contrast is not necessary.

In Which of the Following Situations Should an a Priori