Use the following formula for the variance of a discrete random variable *X* as needed to answer the following problems (round each answer to two decimal places):

## Sample questions

If the variance of a discrete random variable

*X*is 3, what is the standard deviation of*X?***Answer:**1.73The standard deviation is the square root of the variance, so if the variance of

*X*is 3, the standard deviation of*X*is(rounded to two decimal places).

If the standard deviation of

*X*is 0.65, what is the variance of*X?***Answer:**0.42The variance is the square of the standard deviation, so if the standard deviation of

*X*is 0.65, the variance of*X*is (0.65)^{2}= 0.4225. Rounded to two decimal places, the answer is 0.42.

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