SOLUTION: Suppose the scores for a certain test follow a normal distribution with a mean of 78 and a standard deviation of 6. The instructor is going to give the top 10% of scores an A. Wh

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Question 1054201: Suppose the scores for a certain test follow a normal distribution with a mean of 78 and a standard deviation of 6. The instructor is going to give the top 10% of scores an A. What will be the lowest score that receives an A? (Assume the scores are all integers).
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Find the z score for P=0.90.
So then,
z=1.28155
%28x-78%29%2F6=1.28155
x-78=7.689
x=85.689
So then rounding up, an A would be an 86.