Digits (0, 1, 2,. . . ,9) are randomly selected for telephone numbers in surveys. The random

Question:

Digits (0, 1, 2,. . . ,9) are randomly selected for telephone numbers in surveys. The random variable x is the selected digit.
a. Find the mean and standard deviation of x.
b. Find the z score for each of the possible values of x, then find the mean and standard deviation of the population of z scores.
c. Will the same mean and standard deviation as you found in part (b) result from every probability distribution?