For a p chart,UCL = 0.64 and LCL = 0.32.The standard deviation of the proportions is ______.
A) There is not enough information to determine the standard deviation of the proportions
B) 0.32
C) 0.16
D) 0.14
E) 0.11

Question

Quizplus · Accepted Answer

The standard deviation of the proportions can be calculated using the formula for control limits: UCL = p̄ + zσ and LCL = p̄ - zσ. The difference between UCL and LCL is 2zσ. Given UCL = 0.64 and LCL = 0.32, the difference is 0.32, so 2zσ = 0.32. Assuming z = 3 (common for control charts), σ = 0.32 / 6 = 0.0533. However, the closest choice is 0.11, which suggests a different z value or rounding.

For a P Chart,UCL = 0