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Table 2 Sample sizes for different treatment effect sizes and different scale sensitivities to decline

From: Measuring clinical progression in MCI and pre-MCI populations: enrichment and optimizing clinical outcomes over time

   Mean-to-standard deviation ratio of change over time (coefficient of variation)
Sample size per group 0.2 (5) 0.3 (3.3) 0.4 (2.5) 0.5 (2) 0.6 (1.7) 0.7 (1.4) 0.8 (1.3) 0.9 (1.1) 1 (1)
Percentage effect relative to placebo        
20 9,812 4,361 2,453 1,570 1,091 802 614 485 393
25 6,280 2,791 1,570 1,005 698 513 393 311 253
30 4,361 1,939 1,091 698 485 357 274 217 176
35 3,204 1,424 802 513 357 263 202 160 130
40 2,453 1,091 614 393 274 202 155 123 100
45 1,939 862 485 311 217 160 123 97 79
50 1,570 698 393 253 176 130 100 79 64
55 1,298 577 325 209 146 107 83 66 53
60 1,091 485 274 176 123 90 70 55 45
65 929 413 234 150 105 77 60 47 39
70 802 357 202 130 90 67 52 41 34
75 698 311 176 113 79 58 45 36 29
80 614 274 155 100 70 52 40 32 26
85 544 243 137 88 62 46 35 28 23
90 485 217 123 79 55 41 32 25 21
95 435 195 110 71 50 37 29 23 19
100 393 176 100 64 45 34 26 21 17