The quality of an electronic component used in manufacturing cell phones is monitored with a p chart.In the last 20 days,daily samples of 75 units resulted in the following number of defective units per sample: 8,4,3,7,3,1,0,7,4,2,0,1,6,2,4,3,1,2,8,and 5.Find the LCL and UCL for the p chart.
A)[0,.1208]
B)[.0228,.0718]
C)[0,.1897]
D)[.0445,.0501]

Question

Quizplus · Accepted Answer

The LCL and UCL for a p chart are calculated as:LCL = p - 3√(p(1-p)/n)UCL = p + 3√(p(1-p)/n)where p is the sample proportion and n is the sample size.In this case, the sample proportion is:p = (8+4+3+7+3+1+0+7+4+2+0+1+6+2+4+3+1+2+8+5) / (75 * 20) = 0.05Therefore, the LCL and UCL are:LCL = 0.05 - 3√(0.05(1-0.05)/75) = 0UCL = 0.05 + 3√(0.05(1-0.05)/75) = 0.1208

The Quality of an Electronic Component Used in Manufacturing Cell