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Math Help - mean and standard deviation

  1. #1
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    mean and standard deviation

    Hi everyone,

    I'm trying to explain why the following conclusion is not valid:

    A student notes that the Wednesday class had a larger mean homework score than the Tuesday class and then concludes that the standard deviation must be larger in the Wednesday class.

    I know that this can't be true because the two are not dependent on each other, but I tried an example and it seems to be true. When the mean was 8 the standard deviation was 1.30 and when the mean was 240/21 the standard deviation was 12.021.

    Can someone give me a hint on this, please?

    Thank you
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by chocolatelover View Post
    Hi everyone,

    I'm trying to explain why the following conclusion is not valid:

    A student notes that the Wednesday class had a larger mean homework score than the Tuesday class and then concludes that the standard deviation must be larger in the Wednesday class.
    Wed homework scores: 70, 71, 75
    Tue homework scores: 70, 35, 17

    RonL
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