Work out levene test instantly with clear inputs, formula shown and shareable results.
Levene's test runs a one-way ANOVA on the absolute deviations from each group's centre. Using the median rather than the mean gives the Brown-Forsythe variant, which is robust to non-normal data.
Levene's statistic
W = [SS_between/(k−1)] / [SS_within/(N−k)] applied to |xᵢⱼ − median of group j|
Because ANOVA and pooled t-tests assume equal variances; a significant Levene result means you should switch to Welch's correction.
Deviations from the median are less affected by outliers, making the test far more robust than the original mean-based version.