Dana W.

# Variance and Standard deviation

What is the variance and standard deviation for 10,9,9,8,8,8,8,6?

## 2 Answers By Expert Tutors

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Dana W.

Okay, I understand how to find the variance and standard deviation, but when i do the problem i keep getting 9.5 as the sum of the numbers, then divide by 8 (to find the average), and I get 1.1875 as the variance, am I messing up somewhere?
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05/12/14

Francisco E.

the sum of the numbers is not 9.5, I got 66 and the average is 66/8 = 8.25
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05/13/14

Dana W.

I know how to find the average of the data set, and I know the process of finding variance and S.D.  I am asking why the person above divided by 7 instead of 8 after she subtracted the average from the individual numbers, squared the numbers, and then added them up.
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05/13/14

Robert B.

Dana, you are correct the average is 8.25. Person above made a mistake
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05/13/14

Dana W.

Thank you, that answers my question  :)
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05/13/14

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