The mean of a distribution is it's long-running average value. Formally the mean is defined as the expected value which is calculated using the following formulae.
For a discrete random variable (ie. a randomized dice that can only be the integers 1-6):
Where the sum is taken over all possible values of
For a continuous random variable:
The mean of a distribution can be estimated be estimated when the exact probabilities of values are unknown.
Given a sample survey with
The numbers of hours spent studying for a subset of students are 4, 6, 8, 7, 5. Estimate the mean number of hours spent studying for students.