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
| 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 |
$ Assuming 10 participants per group.