TABLE 3.
SAMPLE SIZE ESTIMATES FOR INTERVENTION TRIALS USING LUNG CLEARANCE INDEX AS AN OUTCOME MEASURE
| Treatment Effect | SD | n (α = 0.05) | n (α = 0.01) |
|---|---|---|---|
| 1.0 |
2.0 |
85 |
120 |
| 1.0 |
2.5 |
132 |
186 |
| 1.0 |
3.0 |
190 |
268 |
| 1.5 |
2.0 |
38 |
53 |
| 1.5 |
2.5 |
59 |
83 |
| 1.5 |
3.0 |
85 |
120 |
|
2.0 |
2.0 |
22 |
30 |
| 2.0 |
2.5 |
33 |
47 |
| 2.0 |
3.0 |
48 |
67 |
| 2.5 |
2.0 |
14 |
20 |
| 2.5 |
2.5 |
22 |
30 |
| 2.5 | 3.0 | 31 | 43 |
Treatment effects are based on changes in lung clearance index z scores in a parallel group study, and assume the two treatment groups have the same variability in the outcome measure, assuming an α of 0.05 or 0.01 and a power of 90%. In bold is the treatment effect and SD seen in this trial.