Question 315070
 The time to wait for a particular rural bus is distributed unifromly from 0 to 75 minutes. 100 riders are randomly sampled to learn how long they waited. 
What is the 90th percentile sample average wait time (in minutes) for a sample of 100 riders? 
mean = 0+75/2 = 37.5 
I think I enter the numbers into my scientific calculator under distribution and inverse normal ( percentile, mean, stand dev. / square root of 100) or (.90, 37.5, ?)?? 
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I can't figure out how to get the standard deviation....
Comment: Please consider this.  The range of the data is generally
considered to 6sigma.  Your data range is 0 to 75.
If 6sigma = 75, sigma = 12.5
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Cheers,
Stan H.