Average value: M=(x 1+x2+x3+…+xn)/n (n represents the number of this group of data, and x 1, x2, x3 …+xn represents the specific values of this group of data).

Expected formula: e = x1* p1+x2 * p2+x3 * P3+. +xn * pn。

Extended data

It should be noted that the expected value is not necessarily equal to the common sense "expectation"-"expected value" is not necessarily equal to every result. The expected value is the average of the output values of variables. The expected value is not necessarily contained in the set of output values of variables.

The law of large numbers stipulates that as the number of repetitions approaches infinity, the arithmetic average of numerical values almost inevitably converges to the expected value.