# Expectation value for first success in a binomial distribution?

## Main Question or Discussion Point

This is not a homework problem. Just a curiosity. But my statistics is way rusty.

Suppose a binomial probability distribution with probability p for a success. What is the expected number of trials one would have to make to get your first success? In practice, this means if we took a large number of samples where we stopped at the first success and wrote down the number of trials N to get that success, what is the mean value of N?