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    Sample Mean and Population Mean: Standard Deviation

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    A sample of n= 36 scores is selected form a population with o= 12. if the sample mean of M=56 produces a z score of z= +3.00 then what is the population mean?
    * 56
    *52 (is this correct?)
    * 54
    *50

    A sample of n= 9 scores is obtained from a population with u= 70 and o= 18. if the sample mean is M=76, what is the z-score for the sample mean?
    * z= 0.50
    *z= 1.00
    *z= 0.33 ( is this correct?)
    * z= 3.00

    A random sample of n=4 scores is obtained from a normal population with u= 30 and o= 8. what is the probability that the sample mean will be smaller than M= 22?
    * 0.00003
    * 0.1587 ( is this correct?)
    * 0.3085
    * 0.0228

    a random sample of n= 9 scores is obtained from a normal population with u= 40 and o= 18. what is the probability that the sample mean will be greater than M= 43?
    * 0.1587
    *0.0228
    *0.4325 ( is this correct?)
    * 0.3085

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    https://brainmass.com/statistics/probability/sample-mean-and-population-mean-standard-deviation-584638

    Solution Preview

    1.
    => M-u = z*o/sqrt(n)
    => 56 - u = 3*12/sqrt(36)
    => u = 56 - 3*12/6 = 50

    2.
    z = ...

    Solution Summary

    A few problem related to sample and population mean are solved here.

    $2.19

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