Question

Application Exercise: A university instructor uses different teaching methods on three separate computer science classes. The instructor wants to evaluate the effectiveness of the methods by comparing the grades between the classes. The grades have been transformed and are in the table below. What can the instructor conclude with an a of 0.01? Method A Method B Method с 21 19 21 25 25 20 24 19 17 20 23 20 17 20 34 22 29 26 a) What is the appropriate test statistic? ---Select--- b) Obtain/compute the appropriate values to make a decision about How critical value = ; test statistic = Decision: ---Select--- c) Compute the corresponding effect size(s) and indicate magnitude(s). m2 = ; ---Select- d) Make an interpretation based on the results. O At least one teaching method differs on the grade. O None of the teaching methods differed on the grade. e) Regardless of the Ho decision in b), conduct Tukey's post hoc test for the following comparisons: 2 vs. 3: difference = i significant: ---Select-- V 1 vs. 2: difference = i significant: ---Select--- f) Regardless of the Ho decision in b), conduct Scheffe's post hoc test for the following comparisons: 2 vs. 3: test statistic = ; significant: --Select- 1 vs. 2: test statistic = significant: ---Select-

Answer 1

Using SPSS software

Between-Subjects Factors N Method 1 9 2 9 3 9 Tests of Between-Subjects Effects Dependent Variable:Grade Type III Sum Source of Squares df Mean Square Corrected Model 169.852a 2 84.926 Intercept 14887.259 14887.259 Method 169.852 2 84.926 Error 426.889 24 17.787 Total 15484.000 27 Corrected Total 596.741 26 a. R Squared = 285 (Adjusted R Squared = 225) F 4.775 836.972 Sig .018 .000 .018 1 4.775

Post Hoc Tests Method Multiple Comparisons Dependent Variable:Grade 95% Confidence Interval 1 Sig. 054 .919 .054 Upper Bound .0761 5.7427 9.8538 1 Lower Bound -9.8538 -4.1872 - 0761 .7017 -5.7427 -10.6316 023 10.6316 نيا 1 .919 Mean Difference (I- (1) Method (6) Method J) Tukey HSD 2 -4.8889 3 .7778 2 4.8889 3 5.6667 -.7778 2 -5.6667* Scheffe 2 -4.8889 3 .7778 2 4.8889 3 5.6667" 3 -.7778 2 -5.6667* Based on observed means. The error term is Mean Square(Error) = 17.787. *. The mean difference is significant at the 0.05 level. Std. Error 1.98813 1.98813 1.98813 1.98813 1.98813 1.98813 1.98813 1.98813 1.98813 1.98813 1.98813 1.98813 1 -10.0755 .023 067 .927 .067 .030 4.1872 -.7017 .2977 5.9643 10.0755 10.8532 4.4088 - 4801 -4.4088 - 2977 4801 -5.9643 -10.8532 1 1 .927 030

a) The appropsiate test statistic, f= 4.775 Critical value, fenit = 4 0.01,2,24 = 5.6136 lest statusitic &f=4.775 Deusion: Retain Ho. I fesstical yf n² SS Between 169.852 - 0.28 4 6. Small 596,741 ss Total d). Bus Mom of the tra teaching methods differed on the grade, e) Tukey's post hoc test: (at 250.07 ) aus 3: difference 5-6667 i significant: No 1 us 2. differenu ==4.8889 i significanlı No, Scheff's post moe test text (at <=0.00) test statistic & 2.8503 ? significant: Mo 1 vs 2: kust statistic =-2.4590 significant. Mo, dillesena test statistic Srd. Error