Question

Which of the following does not belong? O the expected value of a variable for a population O the mean of a variable for population O the average of a variable for population all of the above are equivalent

Answer 1

Answer is, option (a), the expected value of a variable for a population .

Explanation: Mean and average are the same thing they tell the value about which the whole data set is concentrated. I.e they are a parameter which represents the whole population.

On the other hand Expected value of a variable can tell different things depending upon what expected value you want to find. For example EV (X) is same as mean. But EV(X^2) will be not same as mean. Similarly ​​, you can find EV of many expressions but they will different from mean.