Red Top Cab Company receives multiple complaints per day about driver behavior. Over 8 days the owner recorded the number of calls to be 3, 0, 8, 9, 6, 7, 9, and 8. What is the upper control limit for the 3-sigma c-chart?
A) 13.35
B) 8.45
C) 6.25
D) 0.00
E) 13.75

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. The average $ \bar{c} $ is $ \frac{3 + 0 + 8 + 9 + 6 + 7 + 9 + 8}{8} = 6.25 $. Plugging this into the formula gives UCL = $ 6.25 + 3\sqrt{6.25} = 6.25 + 3(2.5) = 6.25 + 7.5 = 13.75 $.

Red Top Cab Company Receives Multiple Complaints Per Day About