The problem of estimating the variance of the ratio estimator in sampling with probability proportional to aggregate size is investigated. The form of nonnegative unbiased variance estimators is found ...

The aim of this paper is to provide an overview of sample size estimations for the most frequent type of group studies that result in continuous, binary and ordered categorical outcomes. In recent ...

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 ...

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 ...

Cover Story - Packaging Sterile Packaging: Sample Sizes and Statistics Determining appropriate sample sizes for operational qualifications can help manufacturers ensure sterility of medical device ...

In the first part of this piece I pointed out why it can be difficult to validate TAR using control set metrics. When the overall proportion of responsive documents is very low, it becomes ...