Calculate the variance and standard deviation for samples wi

Calculate the variance and standard deviation for samples with the following statistics: The variance is The standard deviation is

Solution

As

s^2 = [Sum(x^2) - Sum(x)^2 / n] / (n - 1)

Then:

a)

s^2 (variance) = (87 - 26^2 / 13) / (13 - 1) = 2.916666667 = 2.917

s = sqrt(s^2) = 1.707825128 = 1.708

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b)

s^2 (variance) = (366 - 110^2 / 39) / (39 - 1) = 1.466936572 = 1.467

s = sqrt(s^2) = 1.21117157 = 1.211 [answer]

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c)

s^2 (variance) = (16 - 15^2 / 21) / (21 - 1) = 0.264285714 = 0.264

s = sqrt(s^2) = 0.514087263 = 0.514 [answer]