Statistics: 1,001 Practice Problems For Dummies
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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):

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Sample questions

  1. If the variance of a discrete random variable X is 3, what is the standard deviation of X?

    Answer: 1.73

    The standard deviation is the square root of the variance, so if the variance of X is 3, the standard deviation of X is

    image1.jpg

    (rounded to two decimal places).

  2. If the standard deviation of X is 0.65, what is the variance of X?

    Answer: 0.42

    The 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.

If you need more practice on this and other topics from your statistics course, visit 1,001 Statistics Practice Problems For Dummies to purchase online access to 1,001 statistics practice problems! We can help you track your performance, see where you need to study, and create customized problem sets to master your stats skills.

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