matchwhe.blogg.se - Anova gage rr

Moroney in his excellent book " Facts From Figures".

My approach here will slavishly follow that of M.J. On the flights from Minneapolis to San Francisco to Taiwan, I had 17 hours of flight and a 5 hour of layover to think about how ANOVA works. The opportunity to study ANOVA in detail came because of some work I needed to do in Taiwan (a place that I enjoy very much). While I have used ANOVA for years for evaluating the significance of test data, but I have never looked at how it works until very recently. In this post, I am focusing on my self-education on ANOVA and its application to gage R&R. In my case, I will be performing gage R&R on some optical power measurements. A gage is any device that is used to perform a measurement. The class gave me many ideas for improving my experiment design and I highly recommend it to those who do a lot of experiments.įigure 1 shows a caliper, which is a common form of gage (sometimes spelled gauge). As part of the class, we were required to perform some practice Gage Repeatability and Reproducibility (aka gage R&R) studies, which required me to use ANOVA. I took the class because I have been concerned that some of the statistical methods I am currently using for calibrating optics are not as good as they could be. Increase the precision on your measurement tool.I recently took an excellent class at called " Prediction & Tolerance Intervals, Measurement and Reliability" taught by Dr.Analyze more distinct parts that truly represent the entire range of the process.What next? Well, there are two things you can do. A value of 5 or more denotes an acceptable measurement system.When the number of categories is 3, the data can be divided into 3 groups, say low, middle and high.

When the number of categories is 2, the data can be divided into two groups, say high and low.

When the number of categories is less than 2, the measurement system is of no value for controlling the process, since one part cannot be distinguished from another.

So how do you know if your number is high enough? Fortunately, there are guidelines from the Automotive Industry Action Group (AIAG): The higher this number, the better chance the tool has in discerning one part from another. This value represents the number of groups your measurement tool can distinguish from the data itself.

This one metric is something that customers seem to overlook when they call to discuss their Gage studies. Recently I've been thinking about common questions that customers ask when running a Gage R&R analysis in Minitab.įor example, when you run a Gage R&R, the last result that shows up in the session window is a value for the ‘Number of Distinct Categories’.