Table 6.
Power to Detect bs and bi and Average Standard Errors of GMD D from bs and bi
| Power | Average SE of GMA D | ||||
|---|---|---|---|---|---|
| N | Pop GMA D | bs | bi | bs*3 | bi |
| 50 | .30 | .146 | .305 | .365 | .216 |
| 50 | .60 | .384 | .793 | .365 | .216 |
| 100 | .30 | .219 | .508 | .260 | .154 |
| 100 | .60 | .637 | .972 | .260 | .154 |
| 150 | .30 | .297 | .663 | .212 | .126 |
| 150 | .60 | .802 | .998 | .212 | .126 |
| 250 | .30 | .449 | .869 | .165 | .098 |
| 250 | .60 | .947 | 1.000 | .165 | .098 |
| 500 | .30 | .726 | .990 | .117 | .069 |
| 500 | .60 | .999 | 1.000 | .117 | .069 |
| Mdn | .543 | .920 | .212 | .126 | |
Note. Power is the proportion of replications in which bs and bi were statistically significant. Pop GMA D = Population GMA D, bs*3 = GMA D, bi = GMA D. Average SE of GMA D is the Monte Carlo-calculated mean of the Standard Errors of the model-estimated mean differences at end of study--bs*duration (= bs*3) when derived from bs (the slope difference) or bi (the intercept difference).