SOLUTION: question: Scores on a common final exam are normally distributed with a mean of 66 and a standard deviation of 11. Approximately the top 10% of the students will receive an A. Appr

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Question 909689: question: Scores on a common final exam are normally distributed with a mean of 66 and a standard deviation of 11. Approximately the top 10% of the students will receive an A. Approximately, what is the minimum exam score to award an A?
I have tried solving this using the standard normal distribution table but have been unable to get the correct answer of 80.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Scores on a common final exam are normally distributed with a mean of 66 and a standard deviation of 11. Approximately the top 10% of the students will receive an A. Approximately, what is the minimum exam score to award an A?
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Find the z-value with a left tail of 0.90
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invNorm(0.90) = 1.2816
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Find the corresponding score::
x = z*s + u
x = 1.2816*11+66 = 80 when rounded down
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Cheers,
Stan H.
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