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Table 2 Sample size calculations to detect a 10 minute difference in child weekend day moderate-to-vigorous physical activity between intervention and control groups

From: Feasibility trial evaluation of a physical activity and screen-viewing course for parents of 6 to 8 year-old children: Teamplay

SD (mins) α β N required per group Total N required for analysis Total N inflated for attrition Total N rounded and based on 10 participants per course group Number of intervention groups$ Number of control groups$
12 .80 .05 23 46 62.1 80 4 4
12 .80 .01 34 68 91.8 100 5 5
12 .90 .05 31 62 83.7 100 5 5
12 .90 .01 43 86 116.1 120 6 6
17 .80 .05 46 92 124.2 140 7 7
17 .80 .01 68 136 183.6 200 10 10
17 .90 .05 61 122 164.7 180 9 9
17 .90 .01 87 174 234.9 240 12 12
20 .80 .05 63 126 170.1 180 9 9
20 .80 .01 94 188 253.8 260 13 13
20 .90 .05 85 170 229.5 240 12 12
20 .90 .01 120 240 324 340 17 17
  1. $ Assuming 10 participants per group.