Consider a process where specifications on a quality characteristic are 100 t 15. We know that the standard deviation of this quality characteristic is 5. Where should we center the process to minimize the fraction defective produced? Now suppose the mean shifts to 105 and we are using a sample size of 4 on an X chart. What is the probability that such a shift will be detected on the first sample following the shift? What sample size would be needed on a p chart to obtain a similar degree of protection?