Poisson distribution¶
Story¶
The number \(n\) of arrivals of a Poisson process in unit time is Poisson distributed.
Example¶
The number of mutations in a strand of DNA per unit length (since mutations are rare) are Poisson distributed.
Parameters¶
The single parameter is the rate \(\lambda\) of the arrival of the Poisson process.
Support¶
The Poisson distribution is supported on the set of nonnegative integers.
Probability mass function¶
\[\begin{align}
f(n;\lambda) = \frac{\lambda^n}{n!}\,\mathrm{e}^{\lambda}.
\end{align}\]
Usage¶
Package 
Syntax 

NumPy 

SciPy 

Stan 
