SOLUTION: I gave a test to 200 students, and the mean score was a 70. Each SD was 5 pts. How many students scored higher than a 75? 80? (this is a normal bell-curve distribution).

Question 969386: I gave a test to 200 students, and the mean score was a 70. Each SD was 5 pts. How many students scored higher than a 75? 80? (this is a normal bell-curve distribution).
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
I gave a test to 200 students, and the mean score was a 70. Each SD was 5 pts. How many students scored higher than a 75? 80? (this is a normal bell-curve distribution).
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z(75) = (75-70)/5 = 1
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P(x > 75) = P(z > 1) = normalcdf(1,100) = 0.1587
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Ans: 0.1587*200 is approximately 32
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Cheers,
Stan H.
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