D looks right. The sample mean has standard deviation 15/sqrt(25) = 3, so 54.5 is 1.5 standard deviations below the mean and 64.5 is 1.5 standard deviations above.Originally Posted byNICEKID

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- Apr 29th 2005, 02:30 PM #1

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## Help

Is there a correct answer found in my choices. I could not find one.

A sample of 25 is taken from a population which has a normal distribution with a mean of 60 and standard deviation of 15. The probability that the sample mean is between 55.5 and 64.5 is?

A. .0668

B. .2668

C. .5468

D. .8664

E. .9332

- Apr 29th 2005, 07:58 PM #2

- May 13th 2005, 02:18 PM #3

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