What does define mean in math terms?

Answer 1

The mean is sometimes also known as the arithmetic average. For a finite number of observations, it is he sum of their values divided by the total number. It can also be described as the expected value of a variable. If a discrete numerical variable X can take the values x, then the mean is the sum [x*pr(X = x)] where the summation is over all possible values of x. For a continuous variable, replace the summation by integration.