Question 326269: On a test given to all high school students in the state of Maryland, the average score was 82 and the standard deviation was 4.2. If a sample of 100 students is randomly selected, what is the probability that the sample's average is less than 83?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! On a test given to all high school students in the state of Maryland, the average score was 82 and the standard deviation was 4.2. If a sample of 100 students is randomly selected, what is the probability that the sample's average is less than 83?
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Determine the z-score of 83.
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z(83) = (83-82)/[4.2/sqrt(100)] = 1/[0.42] = 2.3810
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P(xbar < 83) = P(z < 2.3810) = 0.9914
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Cheers,
Stan H.
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