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Four Truths and a Lie About Random Variables

APSTAT-NDHSLX

Which of the following statements is not true about random variables?

A

The mean of a random variable is a weighted average which takes into account the probability of each possible outcome.

B

The expected value of a random variable must always be a whole number.

C

The mean and the expected value of a random variable are different vocabulary terms that express the same quantity.

D

Multiplying the values of a random variable by a constant will also multiply the mean of the random variable by that constant.

E

The standard deviation of a random variable is not affected when each of the values of the random variable is increased by the same constant.