The difference between total actual cost incurred and total standard cost applied is referred to as _________________________

Up to three standard deviations above or below the centerline is the amount of variation that statistical process control allows for:

A) Type I errors. B) about 95.5% variation. C) natural variation. D) all types of variation. E) assignable variation.

On average, how many cars are in the system?

In a bank drive-through, there is a single service window and room only for two cars to line-up to wait for service. The mean time between arrivals for drive through customers is 5 minutes. The mean time to complete a customer transaction is 3 minutes. The number of arrivals is distributed according to a Poisson distribution and the service times are exponentially distributed.