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Math Help - Population standard deviation, check answer please

  1. #1
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    Question Population standard deviation, check answer please

    Find the population standard deviation of the following frequency distribution.

    Score Frequency
    1 9
    2 15
    3 6
    total=30
    so, 1*9+2*15+3*6=57

    57/30=1.9

    and, 9(1-1.9)^2+15(2-1.9)^26(3-1.9)^2=14.7

    14.7/30=sqr.49 sqr.49 is my answer, list of possible answers are -
    1.sqr0.49
    2.sqr1.9
    3.sqr2.0
    4.sqr2,2

    thanks for checking
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  2. #2
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    Quote Originally Posted by kwtolley
    Find the population standard deviation of the following frequency distribution.

    Score Frequency
    1 9
    2 15
    3 6
    total=30
    so, 1*9+2*15+3*6=57

    57/30=1.9

    and, 9(1-1.9)^2+15(2-1.9)^26(3-1.9)^2=14.7

    14.7/30=sqr.49 sqr.49 is my answer, list of possible answers are -
    1.sqr0.49
    2.sqr1.9
    3.sqr2.0
    4.sqr2,2

    thanks for checking
    Lookin' good.

    \sqrt{\frac{\sum(x-{\mu})^{2}}{N}}

    \frac{14.7}{30}=0.49

    \sqrt{0.49}=0.7={\sigma}
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  3. #3
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    thanks

    thank you for checking my answer
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