Question 75539
The Director of Emergency Medicine at Big Mountain Medical Services is studying patient waiting time. Waiting time is defined as the time from when a patient enters the facility until seen by a physician. The study indicates the waiting time follows a normal distribution with a mean of 22 minutes and a standard deviation of 8 minutes. 
a. What fraction of the patients is seen in between 15 and 22 minutes? 
P(15<=x<=18)= normalcdf(15,18,22,8)=0.1178
Using TI calculator
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b. What fraction is seen in less than 15 minutes?
= normalcdf(0,15,22,8)
=0.1878
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c. What fraction is seen in more than 15 minutes but less than 32 minutes?
= normalcdf(15,32,22,8)= "can you get this?"
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d. What fraction is seen in more than 25 minutes but less than 32 minutes?
same procedure
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e. Five percent of the patients are seen in how many minutes or less? That is, how quickly are 5 percent of the patients seen? 
InvNorm(0.05,22,8) = 8.84
Rounding down to whole patients you get 8 patients
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Cheers,
Stan H.