The mean time to expose a single panel in a circuit-board plant is 2 minutes with a standard deviation of 1.5 minutes. a. What is the natural coefficient of variation?
b. If the times remain independent, what will be the mean and variance of a job of 60 panels? What will be the coefficiernt of variation of the job of 60?
c. Now suppose times to failure on the expose machine are exponentially dstributed with a mean of 60 hours and the repair time is also exponentially distributed with a mean of 2 hours. What are the effective mean and CV of the process time for a job of 60 panels?
d. Determine the effective mean and CV of the process time for scenario (c) above but with a mean expose time of 1.5 minutes
e. Determine the effective mean and CV of the process time for scenario (c) above but with a mean standard deviation of 0.5 minute.
f. Determine the effective mean and CV of the process time for scenario (c) above but with a mean time between failure 0.5 minutes of 30 hours and a mean time to repair of 1 hour g.
g. Comment on the differences between d, e, and f