Find an Online Tutor Now

Dana W.

asked • 05/12/14

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

By:

Amelia P. answered • 05/12/14

Tutor
5 (29)

Eager to help students succeed at all levels of education!

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?
Report

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
Report

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. 
Report

05/13/14

Robert B.

Dana, you are correct the average is 8.25. Person above made a mistake
Report

05/13/14

Dana W.

Thank you, that answers my question  :)
Report

05/13/14

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.