# statsmodels.robust.norms.TukeyBiweight¶

class statsmodels.robust.norms.TukeyBiweight(c=4.685)[source]

Tukey’s biweight function for M-estimation.

Parameters
cfloat, optional

The tuning constant for Tukey’s Biweight. The default value is c = 4.685.

Notes

Tukey’s biweight is sometime’s called bisquare.

Methods

 Returns the value of estimator rho applied to an input The psi function for Tukey’s biweight estimator The derivative of Tukey’s biweight psi function The robust criterion function for Tukey’s biweight estimator Tukey’s biweight weighting function for the IRLS algorithm