Enter two sample variances and their degrees of freedom to compute the F statistic and critical value and test whether two population variances are equal.
检验两总体方差是否相等。
| Item | Formula / Note | Source / Standard |
|---|---|---|
| F statistic | F = s1^2 / s2^2 (larger variance conventionally placed in the numerator) | Fisher RA, Statistical Methods for Research Workers (1925) |
| Degrees of freedom | df1 = n1 - 1, df2 = n2 - 1 | NIST/SEMATECH e-Handbook of Statistical Methods §1.3.5.9 |
| Critical value | Reject when F > F(1 - alpha; df1, df2) for a right-tailed test | NIST/SEMATECH e-Handbook of Statistical Methods, F distribution |
| Assumptions | Both populations approximately normal and samples independent; not robust to non-normality | NIST/SEMATECH e-Handbook of Statistical Methods §1.3.5.9 |