Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 6

Critical Thinking Alisha is conducting a paired differences test for a "before ( B score) and after ( A score)" situation. She is interested in testing whether the average of the "before" scores is higher than that of the "after" scores.
(a) To use a right-tailed test, how should Alisha construct the differences between the "before" and "after" scores
(b) To use a left-tailed test, how should she construct the differences between the "before" and "after" scores