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 ...

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 ...

Investigator: Right, here is the data set. What is the P value? Statistician: Oh, hello again. Look, I have some concerns about how the endpoint was assessed... Investigator: Fine, I'll add a sentence ...

In two-stage adaptive treatment strategies, patients receive an induction treatment followed by a maintenance therapy, given that the patient responded to the induction treatment they received. To ...

Precedents set in the historic Barr case continue to raise questions over suitable sample-size criteria. "... the number of retests performed before a firm concludes that an unexplained out of ...

Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Somer G. Anderson is CPA, doctor of ...

Random sampling is a random means of gathering data points from all groups. It eliminates bias within your data sets by using ...