8 students were asked to rate how helpful they felt review classes were before & after they took the classes. The instructors felt their classes would be more helpful to students Before S After 6 6 4 4 4 5 8 00 7 696559 10 (Use for 19-21) 19. What is the critical value at the .05 level of significance? 1p 20. What is the test statistic? 4 pts 21. At an 0.05 level of significance, can we conclude that the review classes were helpful? 1pt Using the data above, assume that these were the scores of two groups of 8 students on a quiz either before or after the review class. The researchers want to see if there is any improvement in students having taken the class. (Use for 22- 24) 22. What is the critical value at the .05 level of significance? 1pt 23. What is the test statistic? 4 pts