Statistics

A sample of 12 measurements has a mean of 24 and a standard deviation of 4.5. Suppose that the sample is enlarged to 14 measurements, by including two additional measurements having a common value of 24 each.

Find the standard deviation of the sample of 14 measurements?

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  1. The variance, which was (4.5)^2 = 20.25, is reduced by the ratio 12/14. That is because there are now 14 measurements and the two that were added equaled the previous mean value.

    New variance = 17.357
    New standard deviation = 4.17
    (= sqrt of variance)

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  2. That answer is wrong

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