Statistics question about standard deviation?

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  • fcas80
    Lv 7
    4 months ago

    SD of grouped data s = √ { [ n ([ ∑ f * x^2 ) - (∑ f * x)^2 ]/ [n*(n-1) }

    x … f … f * (x^2) … (f * x)

    51 … 5 … 13005 … 255

    54 … 8 … 23328 … 432

    57 … 12 … 38988 … 684

    60 … 13 … 46800 … 780

    63 … 11 … 43659 … 693

    == … == … ==== … ====

    … … 49…  165780 …2844

     …

    s = √ { [ n ([ ∑ f * x^2 ) - (∑ f * x)^2 ]/ [n*(n-1) }

    = sqrt ( (49* (165780 ) -2844^2)/ (49*48) )

    3.9

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