Variation that occurs when the normal functioning of the process is disturbed by some unpredictable event is known as special cause systematic common cause stochastic Suppose there is a gradual shift in the process level caused by wear in a tool used for cutting so that all the pieces are affected. The signal a potential problem in the process first. chart is most likely to x-bar s-bar R Question 17 _the chance of a false positive. Adding more out-of-control signals to a process control chart will Decrease Increase Not affect Which is not a trend in time series data auto-regressive exponential linear O quadratic