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Thread: Expected Value and Variance

  1. #1
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    Expected Value and Variance

    If a number X is chosen at random from the integers 1, 2, . . . , 100, what is the expected value and the
    variance of X?

    Expected value is just the average? So do I just add 1 to 100 and then divide by 100? Then I am not sure what to do with the variance.
    Any help is appreciated. Thank you

  2. #2
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    Dason's Avatar
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    Re: Expected Value and Variance

    Hi! We are glad that you posted here! This looks like a homework question though. Our homework help policy can be found here. We mainly just want to see what you have tried so far and that you have put some effort into the problem. I would also suggest checking out this thread for some guidelines on smart posting behavior that can help you get answers that are better much more quickly.
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    Dragan's Avatar
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    Re: Expected Value and Variance

    Moreover, simply look up the properties for the mean and variance for a discrete uniform distribution.

  4. #4
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    Khrisstian's Avatar
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    Re: Expected Value and Variance

    The variance characterizes just how much the data differs from your prediction on average. There are a lot of formula's for calculating the variance of a lot of estimators. Right now, you presumably just want to know the variance of your population. Try to find a formula for it.

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