Table 2 Variations in mean IQ, standard deviations and mortality rates: their affect on sample size calculation.
| Â | Â | Â | Â | Â | Â | Total trial size required assuming: | |||
|---|---|---|---|---|---|---|---|---|---|
| Â | Â | Â | Â | Â | Â | 30% mortality | 35% mortality | ||
Mean IQ in control group | SD | Mean IQ in cooled group | SD | Mean difference | Number required to detect this difference (80% power, 5% siq.) | 80% follow up | 75% follow up | 80% follow up | 75% follow up |
75 | 15 | 82.5 | 15 | 7.5 | 126 | 225 | 240 | 243 | 259 |
80 | 15 | 87.5 | 15 | 7.5 | Â | Â | Â | Â | Â |
85 | 15 | 92.5 | 15 | 7.5 | Â | Â | Â | Â | Â |
75 | 20 | 82.5 | 20 | 7.5 | 224 | 400 | 427 | 431 | 460 |
80 | 20 | 87.5 | 20 | 7.5 | Â | Â | Â | Â | Â |
85 | 20 | 92.5 | 20 | 7.5 | Â | Â | Â | Â | Â |
75 | 25 | 82.5 | 25 | 7.5 | 350 | 625 | 667 | 673 | 718 |
80 | 25 | 87.5 | 25 | 7.5 | Â | Â | Â | Â | Â |
85 | 25 | 92.5 | 25 | 7.5 | Â | Â | Â | Â | Â |