Q. In the data set below, what is the variance?5,2,1,1,9,3,7If the answer is a decimal, round it to the nearest tenth.variance (σ2): _____
Calculate Variance: Now, let's do the variance part.We need to sum up each (number−mean)2.So, (5−4)2+(2−4)2+(1−4)2+(1−4)2+(9−4)2+(3−4)2+(7−4)2That's (1)2+(−2)2+(−3)2+(−3)2+(5)2+(−1)2+(3)2Which is 1+4+9+9+25+1+9Sum = 58
Sum of Squares: Finally, divide that sum by the number of data points to get the variance.Variance = 758Variance = 8.2857…Round it to the nearest tenth and we get 8.3
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