Probability Distribution

Consider a random quantity with various possible values, each of which has some associated probability.

A probability distribution is a description of:

  • All possible values of the quantity.
  • The theoretical probability of each value.

Probability distribution of a die roll

The distribution is uniform, meaning that each outcome has the same chance of occurring.


Probability distribution of a statistic
The value of a statistic is random, because it depends on a random Sample.
The probability distribution of the statistic is also known as its sampling distribution.
This describes all possible values of the Statistic and all the corresponding probabilities.