52013-03-08 10:17:14localhostconverted to 1.6 markup42010-07-22 12:06:09PeterWatson32010-07-22 11:36:05PeterWatson22010-07-22 10:11:22PeterWatson12010-07-22 10:10:54PeterWatson

The table below gives the total sample size required for 90% and 80% power for upto 8 groups in a one-way anova. In each case the type I error is taken as 5%. The rows in bold correspond to Cohen's rules of thumb for small, medium and large effect sizes. 90% power 80% power R-squared K=3 K=4 K=5 K=6 K=7 K=8 K=3 K=4 K=5 K=6 K=7 K=8 0.010 1269 1424 1550 1656 1750 1840 969 1096 1200 1290 1372 1448 0.059 207 232 255 270 287 304 159 180 200 216 231 240 0.10 117 132 144 154 163 172 90 103 113 122 130 137 0.138 84 96 105 114 119 128 66 76 80 90 98 104 0.15 76 85 93 100 106 111 58 66 73 79 84 89 0.20 54 61 67 72 77 81 42 49 54 58 62 65 0.25 42 47 52 56 59 63 33 38 42 45 48 51 0.30 33 38 42 45 48 51 27 30 34 37 39 42 0.35 28 31 34 37 40 42 22 25 28 31 33 35 0.40 23 27 29 32 34 36 19 22 24 26 28 30 0.45 20 23 25 27 29 31 16 19 21 23 25 27 0.50 17 20 22 24 26 27 14 16 18 20 22 23 0.55 15 17 19 21 23 24 12 15 16 18 20 21 0.60 13 15 17 19 20 22 11 13 15 16 18 19