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, and 8. What is the upper control limit for the 3-sigma c-chart

upper control limit = 13.34

Step-by-step explanation:

The c-chart is used to check the change in the number of recorded calls per day

First find out the center line

c = sum of recorded calls/number of days

c = (3 + 0 + 8 + 9 + 6 + 7 + 4 + 9 + 8)/9

c = 54/9

c = 6

The upper control limit for 3σ is

upper control limit = c + 3√c

upper control limit = 6 + 3√6

upper control limit = 13.34

Therefore, the upper control limit for the 3-sigma c-chart is 13.34.