F-Statistic Calculator — Formula
## How to Calculate the F-Statistic
### Formula
**F = s1^2 / s2^2**
The F-statistic is the ratio of two sample variances, with the larger variance in the numerator by convention. Under the null hypothesis of equal population variances, F follows an F-distribution with df1 = n1-1 and df2 = n2-1. F-values near 1 suggest equal variances.
### Formula
**F = s1^2 / s2^2**
The F-statistic is the ratio of two sample variances, with the larger variance in the numerator by convention. Under the null hypothesis of equal population variances, F follows an F-distribution with df1 = n1-1 and df2 = n2-1. F-values near 1 suggest equal variances.
Exemplo Resolvido
Group 1: variance = 25, n = 20. Group 2: variance = 16, n = 25.
- F = 25 / 16 = 1.5625
- df1 = 20 - 1 = 19
- df2 = 25 - 1 = 24
- SD ratio = sqrt(1.5625) = 1.25
- Compare F = 1.5625 to F-distribution(19, 24)