# Prior Probability Distribution Concept

## Concept

The Prior Probability Distribution is an aggregate distribution spanning all parts held.

It answers this example question:

“What is the probability of seeing a demand of 3 units for any random part we supply?”

This distribution spans the `mean annual demand `

levels `1`

to `24`

and it is assumed to be a Log Normal Distribution.

# Related Concepts, Formulas, and Guides

## Service Parts Profit Optimization

For more concepts, guides, and formulas related to **Service Parts Profit Optimization** visit the** Firefly Semantics Service Parts Profit** Optimization Help Center: