A professor believes that if a class is allowed to work on an examination as long...
A professor believes that if a class is allowed to work on an examination as long as desired, the times spent by the students would be approximately Normal with mean 42 minutes and standard deviation 6 minutes. The professor should allot how many minutes for the examination if the he wants 90% of the class to finish?
Homework Answers
Given that,
mean =
=
42
standard deviation =
=
6
Using standard normal table,
P(Z < z) = 90%
=(Z < z) = 0.90
= P(Z < z ) = 0.90
z = 1.28
Using z-score formula
x = z
+
x = 1.28 *6+42
x = 49.68=50
X=50
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