Balkin, R. S. (2008) 1
Analyzing a Factorial ANOVA: Non-significant interaction Rick - - PowerPoint PPT Presentation
Analyzing a Factorial ANOVA: Non-significant interaction Rick - - PowerPoint PPT Presentation
Analyzing a Factorial ANOVA: Non-significant interaction Rick Balkin, Ph.D., LPC-S, NCC Department of Counseling Texas A&M University-Commerce Rick_balkin@tamu-commerce.edu Balkin, R. S. (2008) 1 Analyzing a Factorial ANOVA:
Balkin, R. S. (2008) 2
Analyzing a Factorial ANOVA: Non-significant interaction
1.Analyze model assumptions 2.Determine interaction effect
3. Report main effects for each IV 4. Compute Cohen’s f for each IV 5. Perform post hoc and Cohen’s d if necessary. 3. Plot the interaction 4. Analyze simple effects 5. Compute Cohen’s f for each simple effect 6. Perform post hoc and Cohen’s d if necessary.
Non-significant interaction Significant interaction
Balkin, R. S. (2008) 3
Analyzing a Factorial ANOVA: Non-significant interaction
Analyze model assumptions Determine interaction effect Report main effects for each IV Compute Cohen’s f for each IV Perform post hoc and Cohen’s d if necessary
Balkin, R. S. (2008) 4
Analyze model assumptions
Kolmogorov -Smirnov(a) Shapiro-Wilk Gender Statistic df Sig. Statistic df Sig. Men .117 30 .200(*) .972 30 .603 Change in GPA Women .156 30 .060 .924 30 .033
Kolmogorov -Smirnov(a) Shapiro -Wilk Note -Taking methods Statistic df Sig. Statistic df Sig. Method 1 .126 20 .200(*) .916 20 .081 Method 2 .154 20 .200(*) .971 20 .766 Change in GPA Control .144 20 .200(*) .952 20 .392
Balkin, R. S. (2008) 5
Analyze model assumptions
Levene's Test of Equality of Error Variances(a) Dependent Variable: Change in GPA F df1 df2 Sig. .575 5 54 .719 Tests the null hypothesis that the error variance of the dependent variable is equal across groups. a Design: Intercept+gender+method +gender * method
Balkin, R. S. (2008) 6
Determine interaction effect
Tests of Between -Subjects Effects Dependent Variable: Change in GPA Source Type III Sum
- f Squares
df Mean Square F Sig. Partial Eta Squared Corrected Model 1.889(a) 5 .378 11.463 .000 .515 Intercept 4.931 1 4.931 149.582 .000 .735 gender .523 1 .523 15.856 .000 .227 method 1.174 2 .587 17.809 .000 .397 gender * method .193 2 .096 2.921 .062 .098 Error 1.780 54 .033 Total 8.600 60 Corrected Total 3.669 59 a R Squared = .515 (Adjusted R Squared = .470)
Balkin, R. S. (2008) 7
Determine interaction effect
Balkin, R. S. (2008) 8
Report main effects for each IV
Tests of Between -Subjects Effects Dependent Variable: Change in GPA Source Type III Sum
- f Squares
df Mean Square F Sig. Partial Eta Squared Corrected Model 1.889(a) 5 .378 11.463 .000 .515 Intercept 4.931 1 4.931 149.582 .000 .735 gender .523 1 .523 15.856 .000 .227 method 1.174 2 .587 17.809 .000 .397 gender * method .193 2 .096 2.921 .062 .098 Error 1.780 54 .033 Total 8.600 60 Corrected Total 3.669 59 a R Squared = .515 (Adjusted R Squared = .470)
Balkin, R. S. (2008) 9
Compute Cohen’s f/d for each IV
Descriptive Statistics Dependent Variable: Change in GPA Gender Note -Taking methods Mean
- Std. Deviation
N Method 1 .3350 .22858 10 Method 2 .6400 .17764 10 Control .1650 .14916 10 Men Total .3800 .26993 30 Method 1 .1700 .18288 10 Method 2 .3050 .19214 10 Control .1050 .14615 10 Women Total .1933 .18880 30 Method 1 .2525 .21853 20 Method 2 .4725 .24893 20 Control .1350 .14699 20 Total Total .2867 .24938 60
Balkin, R. S. (2008) 10
Compute Cohen’s f/d for each IV
Descriptive Statistics Dependent Variable: Change in GPA Gender Note -Taking methods Mean
- Std. Deviation
N Method 1 .3350 .22858 10 Method 2 .6400 .17764 10 Control .1650 .14916 10 Men Total .3800 .26993 30 Method 1 .1700 .18288 10 Method 2 .3050 .19214 10 Control .1050 .14615 10 Women Total .1933 .18880 30 Method 1 .2525 .21853 20 Method 2 .4725 .24893 20 Control .1350 .14699 20 Total Total .2867 .24938 60
Balkin, R. S. (2008) 11
Perform post hoc and Cohen’s d if necessary
Note -Taking methods
Multiple Comparisons Dependent Variable: Change in GPA Tukey HSD 95% Confidence Interval king methods (J) Note -Taking methods Mean Diffe rence (I-J)
- Std. Error
Sig. Lower Bound Upper Bound Method 2
- .2200(*)
.05741 .001
- .3584
- .0816
Control .1175 .05741 .111
- .0209
.2559 Method 1 .2200(*) .05741 .001 .0816 .3584 Control .3375(*) .05741 .000 .1991 .4759 Method 1
- .1175
.05741 .111
- .2559
.0209 Method 2
- .3375(*)
.05741 .000
- .4759
- .1991
Based on observed means. * The mean difference is significant at the .05 level.