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 […]

# Statistical Engineering

## D2 Values Used in Gage Repeatability and Reproducibility Studies Continuing series on Gage R&R 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 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 […]

## Statistical Engineering – Why Are Designed Experiments Important? Statistical Engineering topics for the Quality Engineer

Statistical Engineering is becoming popular and Statistically Designed Experiments play a big role in the Discovery Process. From time to time there will be a number of factors a Six Sigma Black Belt or Quality Engineer will need to study. In this case, the Six Sigma Practitioner or Quality Engineer may choose to conduct a […]

## Improving Process Capability is a Joint Venture Exercise

Improving process capability is difficult, especially when one party assumes all the responsibility. Recently, I had to support a team getting ready to launch a product. But the customer held up approval since a part feature did not meet specification. Evaluating Process Capability We often use a pre-production run to check the quality of parts. […]