| PGF | Probabilty Generating Function |
| Probability | |
| Expected value | |
| Var | Variance |
| The second factorial moment of |
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.