A researcher would like to test the effectiveness of using imagery to improve the memory of a sample of n = 49 Grade 7 students. Assume that the mean score on a standardized memory test of all the Grade 7 students in Maple Elementary School last year is = 75% with = 10. The sample, after learning how to use imagery for 10 weeks obtained a mean of M = 80%. Conduct a hypothesis test, by calculating thez-score, at = .05, for a two-tailed test. Show all 3 steps. Step 1. State the hypothesis and the alpha level 2. Locate the critical region. 3. Compute the test statistics or z score.