A piza delivery service has an average delivery time of 24 minutes and a slandard deviation of 1.5 minutes. The nominal value is 25 minutes with a tolerance of 5 minutes. Is the delivery process capable at the 4 -sigma level? Is the varisbility too high? Process is not capable because Cpk critical value Process is capable because Cpk> or = critical value; process variability not too high as Cp or = critical value; process variability too high as Cp> itical value