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Math

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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.

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