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Math Help - Percentages using mean and standard deviation

  1. #1
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    Wilmer
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    Percentages using mean and standard deviation

    Mean = 9.32 Standard Deviation = 1.71 for boys
    Mean = 10.04 Standard Deviation =1.83 for girls
    What percent of Boys score above 11?
    What percent of Girls score above 11?
    What percent of Boys score below 8?
    What percent of Girls score below 8?
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  2. #2
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    Re: Percentages using mean and standard deviation

    SDS give us some more info...
    If your mean and standard deviation is the score for an exam..or whatever and the Variable X is normally distributed then you have to standardize it and check from the tables to find the propabilities ...i.e P(Z>11) or P(z<8) etc..... when you get the probabilities multiply them by 100 to get the percentage.....
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