If the specification subgroup size is n = 4 and the known process parameters are ? = 2.75 and ? = .044, the control limits for the $\bar { X }$ chart will be:
A)LCL = 2.684, UCL = 2.816.
B)LCL = 2.728, UCL = 2.772.
C)LCL = 2.618, UCL = 2.882.
D)LCL = 2.518, UCL = 2.998.

Question

Quizplus · Accepted Answer

The control limits for the $\bar{X}$ chart can be calculated using the formula:
UCL = μ + 3(σ/√n)
LCL = μ - 3(σ/√n)

Substituting the given values, we get:
UCL = 2.75 + 3(.044/√4) = 2.816
LCL = 2.75 - 3(.044/√4) = 2.684

Therefore, the control limits for the $\bar{X}$ chart are LCL = 2.684 and UCL = 2.816.

If the Specification Subgroup Size Is N = 4 and the Known