Table 6.
Sample size calculation for a future definitive trial
| Between-arms difference in weekday MVPA (mins) | Power | N students (uninflated) | N students (inflated) | N Schools |
|---|---|---|---|---|
| 10 | 90 | 560 | 800 | 12 |
| 10 | 80 | 420 | 600 | 10 |
| 8 | 90 | 700 | 1000 | 16 |
| 8 | 80 | 560 | 800 | 12 |
| 6 | 90 | 980 | 1400 | 20 |
| 6 | 80 | 840 | 1200 | 18 |
The following parameters were used: cluster size = 70, ICC on weekday MVPA = 0.01 MVPA standard deviation = 20 minutes, correlation between baseline and follow-up MVPA = 0.4, 5 per cent two-sided alpha and inflation to account for 30% of participants not providing primary outcome data.
Values in boldface represent the sample size values proposed for the primary outcome in a future definitive trial