In a Poisson distribution,the variance and standard deviation are equal.

Poisson Distribution

A statistical distribution describing the likelihood of a certain number of events taking place within a specific time or space interval, given that these events happen at a fixed average rate and are independent of the timing of the previous event.

Variance

A statistical measure that represents the degree of spread or dispersion of a set of data values around their mean.

Standard Deviation

A measure of the amount of variation or dispersion in a set of values.