# statsmodels.discrete.discrete_model.Poisson.cdf¶

Poisson.cdf(X)[source]

Poisson model cumulative distribution function

Parameters: X (array-like) – X is the linear predictor of the model. See notes. The value of the Poisson CDF at each point.

Notes

The CDF is defined as

$\exp\left(-\lambda\right)\sum_{i=0}^{y}\frac{\lambda^{i}}{i!}$

where $$\lambda$$ assumes the loglinear model. I.e.,

$\ln\lambda_{i}=X\beta$

The parameter X is $$X\beta$$ in the above formula.