Question 933052: The scores on a sociology exam are normally distributed with a mean of 70 and a standard deviation of 10. If the instructor assigns As to 15%, Bs to 25%, Cs to 40%, Ds to 15%, Fs to 5% of the class, find the cutoff point for grades A-D.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The scores on a sociology exam are normally distributed with a mean of 70 and a standard deviation of 10. If the instructor assigns As to 15%, Bs to 25%, Cs to 40%, Ds to 15%, Fs to 5% of the class, find the cutoff point for grades A-D.
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I'll do the score for A::
invNorm(0.85) = 1.0364
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Corresponding score using x = z*s + u
Cut-off score = 1.0364*10+70 = 80.36
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Cheers,
Stan H.
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