Calculate the variance and standard deviation for samples with the following statistics. a.
n=9,\sum x^(2)=84,\sum x=18
b.
n=41,\sum x^(2)=384,\sum x=90
c.
n=20,\sum x^(2)=16,\sum x=15
a. The variance is
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The standard deviation is
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(Round to the nearest thousandth as needed.)