Magnitude of effect size, t
Taken from Wellek (2003) Table 1.1(v) and page 164
Setting |
Parameter |
Reference Value |
Strict t |
Liberal t |
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Sign Test |
P(difference>0) |
1/2 |
0.10 |
0.20 |
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Mann Whitney |
P[X>Y] |
1/2 |
0.10 |
0.20 |
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2 Binomials |
Log $$\frac{p_text{1}(1-p_text{2})}{(1-p_text{1})p_text{2}} |
0 |
0.41 |
0.85 |
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Paired t |
$$\frac{\mbox{Paired difference}}{\mbox{sd(difference)}}$$ |
0 |
0.25 |
0.50 |
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Unpaired t |
$$\frac{\mbox{Group mean diff}}{\mbox{average group sd}}$$ |
0 |
0.36 |
0.74 |
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One-way ANOVA |
[eta2 (N-k)][(1-eta2 ) mean(N)] |
0 |
0.25 |
0.50 |
where mean(N) is the average group size