stats

Levene's Test

Brown-Forsythe variance homogeneity test for 2–8 groups — W statistic, p-value, and box plots of deviations.

Brown-Forsythe variant (median-based) — more robust than the original mean-based Levene's test. Tests H₀: σ₁² = σ₂² = … = σₖ² (homoscedasticity).
Groups2 / 8
Levene's Test Results
W statistic (F on deviations)
df₁ / df₂
p-value
Conclusion α = 0.05
z_ij = |x_ij − median_j|  ·  W = F(z_ij) = MS_between / MS_within
Brown-Forsythe variant (median-based) — more robust to outliers and skewness
than original mean-based Levene's test.
p via F-distribution (OneWayAnova.tsx pattern).
df₁ = k−1, df₂ = N−k where k = groups, N = total observations.