- Problem 3 (40 points) The mean time to expose a single panel in a circuit board plant is 5mins with a variation of 2 mins. (a) If the times remain independent, what will be the mean and variance of a job of 100 panels? What will be the coefficient of variation of a job of 100 panels? (10 points) (b) Suppose that mean time to failure on the expose machine are exponentially distributed with a mean of 60 hours and repair times are exponentially distributed with a mean of 2 hours. What are the effective mean and CV of the process for a job of 100 panels? (15 points) (c) Suppose the machine needs to have a setup every 10 jobs. The setup times are distributed with a mean of 2 hours and standard deviation of 1.5 hours. What are the effective mean and CV of the process for a job of 100 panels? (15 points)