Have you ever had to prepare an Xbar and R chart? If so, you most likely used some type of software package to display your data and compute the necessary control limits for your Xbar and R chart. But, have you ever wondered how these control limits for an Xbar and R chart were computed? […]

## D2 values for the Distribution of the Average Range Continuing Series in Range Statistics

D2 values for the distribution of the average range appear in the following table. The columns and rows represent the subgroup size (n) and number of subgroups (k). For a given subgroup size, say n=2, notice that the value of d2 changes as the number of subgroups, k, increases. As an example, notice that d2=1.150 […]

## Estimating Gage Repeatability Using Range Statistics Continuing series of articles on Gage R&R and Range Statistics

Estimating Gage Repeatability using Range Statistics for one operator is not all that difficult. Is the same true when estimating Gage Repeatability using Range Statistics when using two operators? Let’s discuss this question in more detail… In a previous post we looked at estimating Gage Repeatability using Range Statistics. In that post we examined one […]