SCENARIO 19-4 She also decides that lower and upper specification limit for the critical-to-quality variable should be
10 and 30 seconds, respectively.
-Referring to Scenario 19-4, suppose the sample mean and range data were based on 6
Observations per hour instead of 5.How would this change affect the lower and upper control
Limits of an R chart?
A) LCL would increase; UCL would decrease.
B) LCL would remain the same; UCL would decrease.
C) Both LCL and UCL would remain the same.
D) LCL would decrease; UCL would increase.

Question

SCENARIO 19-4  She also decides that lower and upper specification limit for the critical-to-quality variable should be
10 and 30 seconds, respectively.
-Referring to Scenario 19-4, suppose the sample mean and range data were based on 6
Observations per hour instead of 5.How would this change affect the lower and upper control
Limits of an R chart?
A) LCL would increase; UCL would decrease. 
B) LCL would remain the same; UCL would decrease. 
C) Both LCL and UCL would remain the same. 
D) LCL would decrease; UCL would increase.

Quizplus · Accepted Answer

Increasing the sample size from 5 to 6 would decrease the Upper Control Limit (UCL) because the control limits are inversely related to the square root of the sample size. The Lower Control Limit (LCL) would remain the same because it is often zero for R charts when the sample size is small.

SCENARIO 19-4 She Also Decides That Lower and Upper