SOLUTION: Having issues with this question please advise. The scores on a national test were normally distributed with a mean of 83 and a standard deviation of 8. If 400 test takers wer

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Question 734181: Having issues with this question please advise.
The scores on a national test were normally distributed with a mean of 83 and a standard deviation of 8. If 400 test takers were selected at random, how many of them would you
expect to have a score lower than 75? (Round to the nearest person)
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The scores on a national test were normally distributed with a mean of 83 and a standard deviation of 8. If 400 test takers were selected at random, how many of them would you
expect to have a score lower than 75? (Round to the nearest person)
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z(75) = (75-83)/[8/sqrt(400)] = -8/[8/20] = -20
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P(x-bar < 75) = P(z < -20) is practically zero.
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Cheers,
Stan H.