.. _variables-poisson_uncertain-lambdas: """"""" lambdas """"""" The parameter for the Poisson distribution, the expected number of events in the time interval of interest .. toctree:: :hidden: :maxdepth: 1 **Specification** - *Alias:* None - *Arguments:* REALLIST **Description** The density function for the poisson distribution is given by: .. math:: f(x) = \frac{\lambda e^{-\lambda}}{x!} where :math:`\lambda` is the frequency of events happening, and ``x`` is the number of events that occur.