Customers difficulty with their internet cable hookup may call an 800 number for technical support. It takes the technician between 30 seconds to 15 minutes to resolve the problem. The distribution of this support time follows the uniform distribution. 
(a)  What are the values for a andb in minutes? (Do not round your intermediate calculations. Round your answer to 1 decimal place.) 
a  [removed] 
b  [removed] 

(b1)  What is the mean time to resolve the problem? (Do not round your intermediate calculations. Round your answer to 2 decimal places.) 
Mean  [removed] 
(b2)  What is the standard deviation of the time? (Do not round your intermediate calculations. Round your answer to 2 decimal places.) 
Standard deviation  [removed] 
(c)  What percent of the problems take more than 5 minutes to resolve? (Do not round your intermediate calculations. Round your answer to 2 decimal places. Omit the “%” sign in your response.) 
Percent  [removed]% 
(d)  Suppose we wish to find the middle 50 percent of the problemsolving times. What are the end points of these two times? (Do not round your intermediate calculations. Round your answers to 3 decimal places.) 
End point 1  [removed] 
End point 2  [removed] 