Question

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 lower control limit for the 3-sigma c-chart?a. 13.35.

b. 0.
c. 9.03.
d. 24.
e. 8.45.

Answer 1

-1.25

Explanation:

The lower control limit for the 3 sigma c chart is :

cbar - 3√cbar

central line = cbar = Σc / n

n = size

Given the data :

3, 0, 8, 9, 6, 7, 9, 8

Σc = 50

n = 8

cbar = 50/8

cbar = 6.25

Lower Control Limit = cbar - 3√cbar

Lower Control Limit = 6.25 - 3√6.25

Lower control limit = 6.25 - 7.5

Lower control limit = -1.25