SOLUTION: The mark 'x' of an exam is normally distributed with a mean of 64 and a standard deviation of 8. If 200 students take the exam, how many students would you expect to obtain a mark

Question 581557: The mark 'x' of an exam is normally distributed with a mean of 64 and a standard deviation of 8. If 200 students take the exam, how many students would you expect to obtain a mark between 64 and 80?
Thank you so much for your help
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The mark 'x' of an exam is normally distributed with a mean of 64 and a standard deviation of 8. If 200 students take the exam, how many students would you expect to obtain a mark between 64 and 80?
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z(64) = 0
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z(80) = (80-64)/8 = 16/8 = 2
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P(60<= x <=64) = P(0<= z <=2) = normalcdf(0,2) = 0.4772
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Cheers,
Stan H.
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