Welch's t test
From Wikipedia, the free encyclopedia
In statistics, Welch's t test is an adaptation of Student's t-test intended for use with two samples having unequal variances. It consists of the statistic
where the denominator is not based on a pooled variance estimate. The degrees of freedom ν associated with this variance estimate is approximated using the Welch-Satterthwaite equation.
Here νi is Ni−1, the degress of freedom associated with the ith mean.
[edit] References
- Welch, B. L. The generalization of "student's" problem when several different population variances are involved. Biometrika. 1947. 34: 28-35
 |
This statistics-related article is a stub. You can help Wikipedia by expanding it. |
