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 15 ounces.
a. The process standard deviation is 0.20, and the process control is set at plus or minus 0.75 standard deviation. Units with
weights less than 14.85 or greater than 15.15 ounces will be classified as defects. What is the probability of a defect (to 4
decimals)?
In a production run of 1000 parts, how many defects would be found (round to the nearest whole number?
b. Through process design improvements, the process standard deviation can be reduced to 0.07. Assume the process control
remains the same, with weights less than 14.85 or greater than 15.15 ounces being classified as defects. What is the probability of
a defect (round to 4 decimals; if necessary)?
In a production run of 1000 parts, how many defects would be found (to the nearest whole number)?
c. What is the advantage of reducing process variation, thereby causing a problem limits to be at a greater number of standard
deviations from the mean?