In: Statistics and Probability
Gender Treatment
Condition
Control MBSR
F 28,
24 12,
8
M 14,
10 14,
18
1. Compute SS(total), SS(within), SS(between-overall) using a 2-way ANOVA.
2. Suppose you treated the data from this experiment as a one-way ANOVA with four groups (i.e., disregarding the factorial arrangement). How would the three sums of squares terms you computed in b, c, and d compare to their counterparts in the one-way approach? Be precise.
(1)
Control | MBSR | Squares Table | |||
F | 28 | 12 | 784 | 144 | |
24 | 8 | 576 | 64 | ||
M | 14 | 14 | 196 | 196 | |
10 | 18 | 100 | 324 | ||
Totals Table | |||||
Control | MBSR | Total | |||
F | 52 | 20 | 72 | ||
M | 24 | 32 | 56 | ||
Total | 76 | 52 | |||
Grand Total | 128 |
Correction Factor, CF = Grand Total^2 /N = 128^2 /8 = 2048
SS Total = Sum of the squares of all the scores - CF = 2384 - 2048 = 336
SS Factor A = (Sum of the squares for the totals of the two levels for factor A / Number of scores in each level) - CF = [(72^2 + 56^2)/4] - 2048 = 32
SS Factor B = (Sum of the squares for the totals of the two levels for factor B / Number of scores in each level) - CF = [(76^2 + 52^2)/4] - 20485 = 72
SS Interaction = (Sum of the squares of the totals of the four levels / Number of scores in each level) - CF - SS Factor A - SS Factor B = [(52^2 + 20^2 + 24^2 + 32^2)/2] - 2048 - 32 - 72 = 200
SS Between = SS Factor A + SS Factor B + SS Interaction = 32 + 72 + 200 = 304
SS Within = SS Total - SS Between = 336 - 304 = 32
(2)
F-C | F-MBSR | M-C | M-MBSR | Squares Table | |||||
28 | 12 | 14 | 14 | 784 | 144 | 196 | 196 | ||
24 | 8 | 10 | 18 | 576 | 64 | 100 | 324 | ||
Counts | 2 | 2 | 2 | 2 | Total Count (N) | 8 | |||
Totals | 52 | 20 | 24 | 32 | Sum of squares = | 2384.00 | |||
Grand Total | 128 | ||||||||
Correction Factor, CF = Grand Total^2 /N = 2048.00
SS Total = Sum of the squares of all the scores - CF = 336.00
SS Between = Sum of the (squares of the totals for the treatments/Number of scores in treatment) - CF = 304.00
SS Within = SS Total - SS Between = 32.00
We observe that the SS values are same for both the ANOVAs.
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