Power analyses and sample size calculations are important parts of many research projects. Often, before data are even collected, it is necessary to calculate and justify the required sample size for ...

Define statistical power List the potential consequences of doing a study that has low power, and also a study that has too much power. Explain what a type 1 and type ...

This web application provides tools for estimating sample size in survival analysis, primarily utilizing Schoenfeld's formula from his 1983 paper "Sample-Size Formula for the Proportional-Hazards ...

We present a simple sample-size formula for weighted log-rank statistics applied to clustered survival data with variable cluster sizes and arbitrary treatment assignments within clusters. This ...

1. Formulas are given, for use under two different conditions of sampling, to determine the number of fruits required in a sample in order to give a desired assurance that a certain accuracy has been ...