When using the X chart the central limit theorem is the basis for a sample size of:
A) 2
B) 3
C) 4
D) 5

Question

Quizplus · Accepted Answer

The X chart is typically used for monitoring the process mean of a variable. According to the central limit theorem, for a large enough sample size (typically n>30), the distribution of sample means will be approximately normal. Thus, a larger sample size would result in a better estimate of the actual mean and a more accurate X chart. Since the question does not provide any additional information about the process or the variable being monitored, it is safest to assume that a sample size of 4 may not be sufficient to rely on the central limit theorem. Therefore, the best choice would be to select a larger sample size, such as C) 4.

When Using the X Chart the Central Limit Theorem Is