The non-central Chi-squared distribution can be used to calculate power for tests detecting departure from a null … distribution. We demonstrate how these calculations can be carried out in Stata using the example of calculating power and sample …

This paper describes how to write Stata programs to estimate the power of virtually any statistical test that Stata can …

This article introduces the Stata menu-driven program steppedwedge, which calculates detectable differences and power …

of second and third level data units only through their product. Simulation results indicate that the OLS-based power and …

The standard formulas for sample size and power calculation, as implemented in the command sampsi, make use of a normal … approximation to the t-distribution. When the sample sizes are small, this approximation is poor, resulting in overestimating power … this work and a command to perform more accurate sample size and power calculations based on the noncentral t …

Royston and Babiker (2002) presented a menu-driven Stata program for the calculation of sample size or power for …

for trials with discrete-time survival endpoints. This article studies the relationship between sample size and power to …. For constant hazard rates, the power depends on the event proportions at the end of the trial in both treatment arms and … on the number of time periods. For varying hazard rates, the power also depends on the shape of the survival functions …