Motorola used the normal distribution to determine the probability of defects an
ID: 2931252 • Letter: M
Question
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 14 ounces a. The process standard deviation is 0.10, and the process control is set at plus or minus 1.25 standard deviation s. Units with weights less than 13.875 or greater than 14.125 ounces will be classified as defects. What is the probability of a defect (to 4 decimals)? 0.1336 In a production run of 1000 parts, how many defects would be found (round to the nearest whole number)? 134 8 b. Through process design improvements, the process standard deviation can be reduced to 0.08. Assume the process control remains the same, with weights less than 13.876 or greater than 14.125 ounces being classified as defects. What is the probability of a defect (round to 4 decimals; if necessary)? 0026 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?Explanation / Answer
a) probability of defect=P(X<13.875)+P(X>14.125)=P(Z<-1.25)+P(Z>1.25)=0.10565+0.10565=0.2113
number of defects to be found ~ 211
b) probability of defect=P(X<13.875)+P(X>14.125)=P(Z<-0.125/0.08)+P(Z>0.125/0.08)=P(Z<-1.5625)+P(Z>1.5625)
=0.1182
number of defects to be found =~ 118
c)