Morgan has calculated the upper and lower limit for control limits in an chart. She doesn't have the software available to create these charts automatically, so she determines what happens to these limits if n decreases. Suppose Morgan is now using a smaller sample size, but she has forgotten to adjust the upper and lower limits to reflect the smaller sample size. What is likely to occur as she manually plots observations on the chart?

Question

Morgan has calculated the upper and lower limit for control limits in an  chart. She doesn't have the software available to create these charts automatically, so she determines what happens to these limits if n decreases. Suppose Morgan is now using a smaller sample size, but she has forgotten to adjust the upper and lower limits to reflect the smaller sample size. What is likely to occur as she manually plots observations on the chart?

Quizplus · Accepted Answer

The Answer is The limits are narrower with larger samples, so she is likely to observe more observations that lie outside these limits. She might decide she is observing out-of-control behavior.

Morgan Has Calculated the Upper and Lower Limit for Control