Red Top Cab Company receives multiple complaints per day about driver behavior. Over 9 days the owner recorded the number of calls to be 3, 0, 8, 9, 6, 7, 4, 9, 8. What is the upper control limit for the c-chart?
A) 13.35
B) 8.45
C) 24.00
D) 0.00
E) 9.03

Question

Quizplus · Accepted Answer

The upper control limit (UCL) for a c-chart is calculated using the formula UCL = $ \bar{c} + 3\sqrt{\bar{c}} $, where $ \bar{c} $ is the average number of complaints per day. For the given data, $ \bar{c} = \frac{3 + 0 + 8 + 9 + 6 + 7 + 4 + 9 + 8}{9} = \frac{54}{9} = 6 $. Thus, UCL = $ 6 + 3\sqrt{6} \approx 6 + 3(2.45) = 6 + 7.35 = 13.35 $.

Red Top Cab Company Receives Multiple Complaints Per Day About