Hartley F-max
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The Hartley F-max calculator tests variance homogeneity across groups. It compares the largest variance (s²_max) to the smallest variance (s²_min) using the ratio F = s²_max / s²_min. This test is ideal to verify if groups have similar variability, a key assumption for analyses like ANOVA.
The Hartley test formula requires normal distribution and equal sample sizes. If the calculated F value exceeds the critical value (from statistical tables), the null hypothesis of homogeneous variances is rejected. Use this tool before analyses that rely on constant variance.
Note: Hartley's test is sensitive to deviations from normality and unequal sample sizes. For uneven samples, consider robust alternatives like Levene's or Bartlett's test. Always validate test assumptions before interpreting statistical results.
Frequently asked questions
What does the Hartley F-max test do?
It checks if groups have statistically equal variances, a requirement for ANOVA and similar analyses.
When should I use this test?
Use it before analyses requiring homogenous variances and when sample sizes are equal across groups.
How to interpret the F value?
If F exceeds the critical value (from tables), variances are heterogeneous. Otherwise, they are considered homogeneous.
What are the limitations of Hartley's test?
It's sensitive to unequal sample sizes and non-normal distributions. Use Levene's or Bartlett's test in such cases.