The mean of the sample means and the pooled standard deviation of 50 samples of size 10 taken from a production process under control are found to be 225 and 16,respectively.The upper control limit for the chart is:
A)231.79
B)240.18
C)218.21
D)209.82

Question

The mean of the sample means and the pooled standard deviation of 50 samples of size 10 taken from a production process under control are found to be 225 and 16,respectively.The upper control limit for the  chart is:
A)231.79 
B)240.18 
C)218.21 
D)209.82

Quizplus · Accepted Answer

The upper control limit for the 11ea78b9_2e5f_464f_8379_49142e3d3d30_TB4388_11 chart can be calculated using the formula:

UCL = X̅ + A2 * σ

Where,
X̅ = Mean of sample means = 225
A2 = Constant value from the control chart factors table for n=10 = 0.728
σ = Pooled standard deviation = 16

UCL = 225 + 0.728 * 16
UCL = 240.18

Therefore, the upper control limit for the chart is 240.18, which corresponds to choice B.

The Mean of the Sample Means and the Pooled Standard