What is the variance of the following numbers?: {2,9,3,2,7,7,12}

1 Answer
Alan P.
Apr 10, 2016

Variancepop.≈12.57

Explanation:

Given the terms: {2,9,3,2,7,7,12}

Sum of terms: 2+9+3+2+7+7+12=42
Number of terms: 7
Mean: 427=6

Deviations from Mean: {|2−6|,|9−6|,|3−6|,|2−6|,|7−6|,|7−6|,|12−6|}

Squares of Deviations from Mean: {(2−6)2,(9−6)2,(3−6)2,(2−62),(7−6)2,(7−6)2,(12−6)2}

Sum of Squares of Deviations form Mean: (2−6)2,+(9−6)2+(3−6)2+(2−62)+(7−6)2+(7−6)2+(12−6)2=88

Population Variance =Sum of Squares of Deviations from MeanCount of Terms=887≈12.57

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