A computer repair shop has two work centers. The first center examines the computer to see what is wrong, and the second center repairs the computer. Let x1 and x2 be random variables representing the lengths of time in minutes to examine a computer (x1) and to repair a computer (x2). Assume x1 and x2 are independent random variables. Long-term history has shown the following times.

Examine computer, x1: 1 = 28.1 minutes; 1 = 7.5 minutes

Repair computer, x2: 2 = 90.7 minutes; 2 = 15.3 minutes

Let W = x1 + x2 be a random variable representing the total time to examine and repair the computer. Compute the mean, variance, and standard deviation of W. Round your answer to the nearest tenth.

Explain how you got your answer