QUESTION 5 Problem A An educator is interested in exploring how a short refresher course covering correlated- and independent-samples t tests would affect students' knowledge and skills in preparation before a major examination. Fifteen randomly selected students completed a pretest before taking the refresher course. Two days following the refresher course, all fifteen students completed a posttest. Use a = .05two-tail to determine whether there was a significant change in scores. What is the value of Cohen's d? Enter the answer to two decimal places and be sure to put in a negative sign. QUESTION 6 Problem A What is the lower real limit of the confidence interval? (Be sure to round the estimated standard error of difference scores to four places and the t-crit to three places when making this calculation and report the final answer to two decimal places) QUESTION 7 Problem A What is the upper real limit of the confidence interval? (Be sure to round the estimated standard error of difference scores to four places and the t-crit to three places when making this calculation and report the final answer to two decimal places)