# Math Help - Geometric distribution

1. ## Geometric distribution

Hello everybody!

Let ^ be random independent variables with geometric distribution.

Find

Which form of the geometric distribution are you using: $\Pr(X = k) = (1-p)^{k-1}p$ for k = 1, 2, ..., or $\Pr(X=k) = (1 - p)^kp$ for k = 0, 1, ...?