Name this value found by adding a set of numbers and dividing by the number of values in  the set.
Two values of this quantity are compared in a two-sample 𝑡-test. In a chi-squared [KYE "squared"]   distribution, this value is equal to the number of degrees of freedom. For a function, this value can  be calculated by dividing its integral by the width of the interval of the integral. Often represented   by a letter with a bar over it, this number for a distribution is equal to the expected value. There are  harmonic and geometric versions of this quantity, the latter of which is found by taking the root of a  product. Name this value found by adding a set of numbers and dividing by the number of values in  the set.
Two values of this quantity are compared in a two-sample 𝑡-test.
arithmetic mean [accept average; accept expected value before it is mentioned]