statsmodels.robust.norms.TukeyBiweight.rho¶

TukeyBiweight.rho(z)[source]¶

The robust criterion function for Tukey’s biweight estimator

Parameters:¶

zarray_like

1d array

Returns:¶

rhondarray

rho(z) = -(1 - (z/c)**2)**3 * c**2/6 + c**2/6 for |z| <= R

rho(z) = 0 for |z| > R