SOLUTION: I am having a very hard time with this problem! Please help! The time a group of high school students arrive home from school each day was found to be normally distributed. Th

Question 77800: I am having a very hard time with this problem! Please help!

The time a group of high school students arrive home from school each day was found to be normally distributed. The mean time was 3:15 PM and the times had a standard deviation of 15 minutes. What is the probability that a student chosed at random arrives home from school before 2:30 PM?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The mean time was 3:15 PM and the times had a standard deviation of 15 minutes. What is the probability that a student chosen at random arrives home from school before 2:30 PM?
-----------------
3:15 corresponds to zero on the z-distribution.
If the standard deviation is 15 minutes, 2:30
would be three standard deviation to the left
of the mean.
The probability that z<-3 = 0.0013499
-----
Let me know if you do not understand this and
what it is you do not understand.
Cheers,
Stan H.
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