motorola used the normal distribution to determine the probability of defects and the number of defects expected in a production process. assume a production process produces items with a mean weight of 13 ounces. a. the process standard deviation is 0.15 , and the process control is set at plus or minus 1.6 standard deviation. units with weights less than 12.76 or greater than 13.24 ounces will be classified as defects.