Quality by Experimental Design – 4th Edition | Book Publication Announcement Quality by Experiment Design is due for release February 17, 2016. Are you interested in designing experiments that try to solve technical problems tied to strategic business, productivity or innovation initiatives? If so, then Quality by Experimental Design is a great companion text that will […]

# Statistical Engineering

## Control Chart Constants – How to Derive A2 and E2 [GUIDE]

Control Chart Constants, where did the A2 and E2 constants come from? In statistical process control (SPC) charting, we use the A2 and E2 constants to calculate control limits for an Average (X-bar chart) and Individuals charts. But where do the A2 and E2 constants come from? Let’s look at the following example, for an X-bar […]

## D2 values for the Distribution of the Average Range [Tutorial]

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 […]

## D2 Values Used in Gage Repeatability and Reproducibility Studies

D2 values appear in Gage RR equations when using the Average and Range method. The Average and Range method uses constants to estimate Gage Repeatability and Reproducibility (GR&R). There are two “K” constants “K1” and “K2”. Quality Engineers use them to estimate repeatability and reproducibility. Each of these “K” constants use d2 values in their […]

## Estimating Gage Repeatability Using 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 […]