Question 1179205
the waiting time follows  normal distribution.
mean is 25 minutes.
standard deviation is 5.3 minutes.
probability she will have to wait long than 18 minutes before seeing the doctor is .9067 using the calculator at:
https://davidmlane.com/hyperstat/z_table.html
here are the results:


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there are other ways to do it, but this is the easiest.


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