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December 19, 2014

December 19, 2014

Posted by **Anonymous** on Sunday, November 8, 2009 at 8:45am.

{8.5, 4.5, 8.8, 6.9, 5.3}

- Math -
**PsyDAG**, Sunday, November 8, 2009 at 10:49amFirst find the mean. Then find the difference of each score from the mean. (As a check, the sum of these differences should be zero.) Square each difference and find their sum. Divide that sum by n (number of scores) to get your variance.

I'll let you do the work.

I hope this helps. Thanks for asking.

- Math -
**Anonymous**, Sunday, November 8, 2009 at 11:03amI wouldn't want you to do the work, so thank you!

Mean is 6.8

6.8-8.5=-1.7^2=2.89

6.8-4.5=2.3^2=5.29

6.8-8.8=-2^2=4

6.8-6.9=-0.1^2=0.1

6.8-5.3=1.5^2=2.25

14.53/5=2.906

1.705

- PsyDAG -
**Anonymous**, Sunday, November 8, 2009 at 11:08amIs my work correct? I think I messed up somewhere in the process.

- Math -
**Anonymous**, Sunday, November 8, 2009 at 11:13amAnd I wanted to ask is it standard for the sums to always add up to 0? Thank you for that tip.

- Math -
**PsyDAG**, Sunday, November 8, 2009 at 11:14amDoesn't .1 * .1 =.01?

However, I did not check the whole process.

- Math -
**PsyDAG**, Sunday, November 8, 2009 at 11:17amThe sum of the differences from the mean will always add to zero, assuming that you have not made a mistake.

Remember that the mean acts as a balance point for the distribution, so the scores on one side (+) must equal the scores on the other (-).

- Math -
**Anonymous**, Sunday, November 8, 2009 at 11:19amMean is 6.8

6.8-8.5=-1.7^2=2.89

6.8-4.5=2.3^2=5.29

6.8-8.8=-2^2=4

6.8-6.9=-0.1^2=0.01

6.8-5.3=1.5^2=2.25

14.44/5=2.888 So the variance is 2.9!!

1.6994

Wow! Thanks for catching that, it changed the entire process. I appreciate your help.

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