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 ...

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 ...

The probability that the null hypothesis will be rejected when it is actually true is called the false positive rate and is determined by the significance level of the test (called alpha which is ...

Low statistical power undermines the purpose of scientific research; it reduces the chance of detecting a true effect. Perhaps less intuitively, low power also reduces the likelihood that a ...

Journal of the Royal Statistical Society. Series D (The Statistician), Vol. 46, No. 2, Special Issue: Sample Size Determination (1997), pp. 231-237 (7 pages) A simple general formula is given for ...