statsmodels.robust.norms.TukeyBiweight.rho#
- TukeyBiweight.rho(z)[source]#
The robust criterion function for Tukey’s biweight estimator
- Parameters:
- zarray_like
1d array
- Returns:
- rho
ndarray rho(z) = (c**2 / 6) * (1 - (1 - (z/c)**2)**3) for |z| <= c
rho(z) = c**2 / 6 for |z| > c
- rho