Customers experiencing technical difficulty with their Internet cable hookup may call an 800 number for technical support. It takes the technician between 90 seconds to 12 minutes to resolve the problem. The distribution of this support time follows the uniform distribution. a. What are the values for a and bin minutes? (Do not round the intermediate calculations. Round the final answers to 1 decimal place.) a 1.5 b 12 b-1. What is the mean time to resolve the problem? (Do not round the intermediate calculations. Round the final answer to 2 decimal places.) Mean b-2. What is the standard deviation of the time? (Do not round the intermediate calculations. Round the final answer to 2 decimal places.) Standard deviation c. What fraction of the problems take more than 5 minutes to resolve? (Do not round the intermediate calculations. Round the final answer to 2 decimal places.) Percent % d. Suppose we wish to find the middle 50% of the problemsolving times. What are the end points of these two times? (Do not round the intermediate calculations. Round the final answers to 3 decimal places.) Lower end point Upper end point