Question 21:

A set of progressive relaxation exercises was shown on videotape to an Experimental Group (EG) of 38 subjects, while set of neutral videotape was shown to a Control Group (CG) of 23 patients who were also on chronic hemodialysis. The results of a psychiatric questionnaire are presented below: Pretest Posttest Mean sd n Mean sd Experimental 37.51 10.66 38 33.42 10.18 Control 36.42 8.59 23 39.71 9.16 " 38 23 We want to perform a statistical test to compare pretest scores of EG and CG. What is the correct test statistics to compare variance of EG and CG? F-test T-test Z-test