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Comparing amount of time spent watching TV per day by age group.


Analysis of Variance (ANOVA): TVHOURS (Means) by AGECAT4 (Groups)


Independent Variable Label: Age categories

Dependent Variable Label: Hours watch TV per day


Group Summary Statistics


            Group          N             Mean        Std. Dev.


            18-29        185          3.0108           2.2698

            30-39        243          2.6008           2.0331

            40-49        198          2.5859           1.7712

              50+        364          3.2665           2.6385




Analysis of Variance


                  Sum of Squares        df       Mean Squares


Between Groups          92.09          3 A         30.70 B

 Within Groups        5093.45        986 C          5.17 D

         Total          5185.54        989 E  


                    F Statistic              p <


                         5.94 F        0.0005 G




A   k-1, where k = 4 group means

B   Between Groups Sum of Squares degrees of freedom

C   n-k, where n = 990

D   Within Groups Sum of Squares degrees of freedom

E   n-1

F   Between Groups Mean Squares Within Groups Mean Squares

G   The F-Statistic is statistically significant.  The p-value represents the probability of making a type 1 error (concluding there is statistical significance when there is none).  Since there is about .05% (p < .0005) chance of making a type 1 error, you conclude there is statistical significance; ie, there is variation among the groups.



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