SOLUTION: After the first exam the professor reports to the class that the mean for the exam was 73, and the standard deviation was 7. If the bottom 10% of the class fail the exam, what s

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Question 286222: After the first exam the professor reports to the class that the mean for the exam was 73, and the standard deviation was 7.
If the bottom 10% of the class fail the exam, what score would earn a student a failing grade?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
After the first exam the professor reports to the class that the mean for the exam was 73, and the standard deviation was 7.
If the bottom 10% of the class fail the exam, what score would earn a student a failing grade?
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Find the z-value with a 10% left tail:
invNorm(0.10) = -1.2816...
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Find the score corresponding to that z-score:
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x = zs+u
x = -1.2816*7 + 73
x = 64.029
Scores below that fail.
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Cheers,
Stan H.