Question 561523: .A final exam in Math 160 has a mean of 73 with standard deviation 7.73. Assume that a random sample of 24 students is selected and the test score of the sample is computed. Assuming the scores are normally distributed, what percentage of sample means are less than 69
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A final exam in Math 160 has a mean of 73 with standard deviation 7.73. Assume that a random sample of 24 students is selected and the test score of the sample is computed. Assuming the scores are normally distributed, what percentage of sample means are less than 69
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mean of all samples of size 24: 73
std of all samples of size 24: 7.73/sqrt(24) =
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t(69) = (69-73)/[7.73/sqrt(24)] = -2.535
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P(x < 69) = P(z < -2.535) = tcdf(-100,-2.535,23) = 0.0093
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Cheers,
Stan H.
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