# Math

posted by on .

Find the variance for the given data. Round your answer to one more decimal place than the original data.
{8.5, 4.5, 8.8, 6.9, 5.3}

• Math - ,

First 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 - ,

I 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 - ,

Is my work correct? I think I messed up somewhere in the process.

• Math - ,

And I wanted to ask is it standard for the sums to always add up to 0? Thank you for that tip.

• Math - ,

Doesn't .1 * .1 =.01?

However, I did not check the whole process.

• Math - ,

The 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 - ,

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=0.01
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.