# Math Help - Conditional poisson question

1. ## Conditional poisson question

Suppose the number of earthquakes in a given year is a Poisson random variable with parameter lambda > 0. Suppose in addition that each earthquake that occurs has a probability p of being catastrophic (independently of the nature of other earthquakes). Find the expectation and variance of the number of catastrophic earthquakes in a given year.

2. Originally Posted by blues360
Suppose the number of earthquakes in a given year is a Poisson random variable with parameter lambda > 0. Suppose in addition that each earthquake that occurs has a probability p of being catastrophic (independently of the nature of other earthquakes). Find the expectation and variance of the number of catastrophic earthquakes in a given year.