A manager wants to build 3-sigma control limits for a process. The target value for the mean of the process is 10 units, and the standard deviation of the process is 6. If samples of size 9 are to be taken, the UCL and LCL will be
A) -8 and 28
B) 16 and 4
C) 12 and 8
D) 4 and 16
E) 8 and 12

Question

Quizplus · Accepted Answer

The 3-sigma control limits are calculated using the formula: mean ± 3*(standard deviation/sqrt(sample size)). Here, mean = 10, standard deviation = 6, and sample size = 9. So, the control limits are 10 ± 3*(6/sqrt(9)) = 10 ± 6 = 16 (UCL) and 4 (LCL).

A Manager Wants to Build 3-Sigma Control Limits for a Process