Question

Which of the following scenarios lends itself to using X-bar and R Chart control charts?

Select one:
a. Data count in each subgroup is less than 8
b. Data is static
c. Data cannot be grouped into subgroups, letting you chart the mean of each group
d. Data count in each subgroup is more than 100

Answer 1

X-bar and R Chart control charts are most suitable when the data count in each subgroup is less than 8, as these charts are optimal for smaller sample sizes and require multiple samples to calculate subgroup means and ranges. Therefore, the correct answer is option a. Data count in each subgroup is less than 8.

Step-by-step explanation:

The scenario that lends itself to using X-bar and R Chart control charts is when the data count in each subgroup is less than 8. This is because X-bar and R charts are designed to monitor the process mean and process variation when samples are of a smaller size, typically between 2 to 10 observations per subgroup. When data points within a subgroup are more than 100, it is often more appropriate to use an X-bar and S Chart due to the larger sample size which assumes that the sample standard deviation is a better estimate of the population standard deviation than the range. If data is static, there are no subgroups over time to chart, and if data cannot be grouped into subgroups, the X-bar and R charts are not applicable as they require multiple samples to calculate ranges and means for each subgroup.