statsmodels.genmod.families.varfuncs.NegativeBinomial

class statsmodels.genmod.families.varfuncs.NegativeBinomial(alpha=1.0)[source]

Negative binomial variance function

Parameters:
alphafloat

The ancillary parameter for the negative binomial variance function. alpha is assumed to be nonstochastic. The default is 1.

Notes

Formulas :

V(mu) = mu + alpha*mu**2

Alias for NegativeBinomial: nbinom = NegativeBinomial()

A private method _clean trims the data by machine epsilon so that p is in (0,inf)

Methods

call

Returns the negative binomial variance

Methods

deriv(mu)

Derivative of the negative binomial variance function.


Last update: Jun 14, 2024