geometric distribution

noun1

1. •
   Either of two slightly different discrete probability distributions, each based on repetitions of a trial with "success" probability p: (1) the number X of trials required to obtain one success, or (2) the number Y = X − 1 of failed trials before the first success.

   • Recall that we have already calculated the mean and variance for the geometric distribution case (r = 1) in Example 5.17. — 2009