../pkgdown.css" rel="stylesheet"><script src="../pkgdown.js"></script><meta property="og:title" content="Welch's rectified degree of freedom — WelchDegreeOfFreedom"><meta property="og:description" content="When variance across groups are heterogeneous,
the Student t distribution with n - 1 df is not the exact distribution.
However, (Welch 1947)
, using methods of moments, was able to find the
best-fitting t distribution. This distribution has degree of freedom reduced
based on the sample sizes and the var