A major airline is interested in monitoring customer satisfaction with its baggage handling process. To do so, each day the airline randomly selects 100 customers and surveys them to determine if they are satisfied or not with the service provided. After 20 samples, a total of 260 unsatisfied customers were counted. The lower and upper control limits for the appropriate control chart for these data are
A) 0.0292 and 0.2308
B) 0 and 0.2308
C) 0.0964 and 0.1363
D) 0 and 0.4236
E) indeterminate

Question

Quizplus · Accepted Answer

The control chart for proportions (p-chart) is used here. The average proportion of unsatisfied customers is 260/(20*100) = 0.13. The standard deviation is sqrt[(0.13)(0.87)/100] = 0.0335. The control limits are 0.13 ± 3(0.0335), which are approximately 0.0292 and 0.2308.

A Major Airline Is Interested in Monitoring Customer Satisfaction with Its