Table 3 A and B. Required number of replicates: A) Number of times a study would have to be repeated with the same conclusion to achieve an α of 0.00001, 0.0001, 0.001, 0.01, 0.05, 0.1, and 0.2, at critical effects sizes of 1, 2, and 4 SD, for an independent two-tailed, two sample t-test. (B) Number of times a study would have to be repeated with the same conclusion to achieve a β of 0.00001, 0.0001, 0.001, 0.01, 0.05, 0.1, and 0.2, at critical effects sizes of 1, 2, and 4 SD, for an independent two-tailed, two sample t-test
From: Optimal alpha reduces error rates in gene expression studies: a meta-analysis approach
A. | ||||||||
Critical effect size | Within-study replication | Replication of the experiment needed to achieve | ||||||
α = 0.00001 | α = 0.0001 | α = 0.001 | α = 0.01 | α = 0.05 | α = 0.1 | α = 0.2 | ||
1 SD | 4 | 10 | 8 | 6 | 4 | 3 | 2 | 2 |
6 | 9 | 7 | 5 | 4 | 3 | 2 | 2 | |
8 | 8 | 6 | 5 | 3 | 3 | 2 | 2 | |
10 | 7 | 6 | 4 | 3 | 2 | 2 | 1 | |
2 SD | 4 | 7 | 5 | 4 | 3 | 2 | 2 | 1 |
6 | 5 | 4 | 3 | 2 | 2 | 1 | 1 | |
8 | 4 | 4 | 3 | 2 | 1 | 1 | 1 | |
10 | 4 | 3 | 2 | 2 | 1 | 1 | 1 | |
4 SD | 4 | 4 | 3 | 2 | 2 | 1 | 1 | 1 |
6 | 3 | 2 | 2 | 1 | 1 | 1 | 1 | |
8 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | |
10 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | |
B. | ||||||||
Critical effect size | Within-study replication | Replication of the experiment needed to achieve | ||||||
β = 0.00001 | β = 0.0001 | β = 0.001 | β = 0.01 | β = 0.05 | β = 0.1 | β = 0.2 | ||
1 SD | 4 | 12 | 10 | 8 | 5 | 4 | 3 | 2 |
6 | 10 | 8 | 6 | 4 | 3 | 2 | 2 | |
8 | 9 | 7 | 6 | 4 | 3 | 2 | 2 | |
10 | 8 | 6 | 5 | 3 | 2 | 2 | 2 | |
2 SD | 4 | 6 | 5 | 4 | 3 | 2 | 2 | 1 |
6 | 5 | 4 | 3 | 2 | 2 | 1 | 1 | |
8 | 4 | 3 | 3 | 2 | 1 | 1 | 1 | |
10 | 4 | 3 | 2 | 2 | 1 | 1 | 1 | |
4 SD | 4 | 3 | 3 | 2 | 2 | 1 | 1 | 1 |
6 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | |
8 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | |
10 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | |