What's Up, Post-hoc?

What's Up, Post-hoc?

If there is a difference, what is it?

Last month, I described a simple problem to determine which gear material resulted in longer wear. We reviewed the extremely powerful technique called Analysis of Variance (ANOVA) and found a statistically significant and important effect on the average wear due to gear material. I also promised to tell you about an infrequently used next step that would make you a lot of money.  That is what we are going to talk about this month.

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Homoscedasticity

Homoscedasticity

Nothing to be afraid of

For the last couple of columns, we have been analyzing a simple experiment where we look for the best choice for a new gear material. We have used analysis of variance (ANOVA) to detect a difference in the mean wear for the four different materials. In the last column, we performed a post-hoc test to determine which means were actually different from one another. However, to find the best solution, we need to know true costs, and to get that I need to know the variability associated with the different materials. At the end of the article, I’ll give you a chance to show off —the first one to e-mail me the correct cost analysis will get bragging rights and their name (or reasonably tasteful nom de plume if you prefer) in print.

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Show Me The Money

Show Me The Money

Choosing the Right Material (finally!)

If you have been following my articles for the last few months, you know that we’re almost done with an experimental analysis and that today we will be doing the final step—making our company money. If you haven’t been following my articles, then you should probably be flogged with a soggy noodle until you admit to your other crimes in a tearful confession posted on YouTube.

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Six Sigma and the Corner Office

Six Sigma and the Corner Office

Translating Plans into Action

I thought this month we would get away from the stats of the last few columns. Hey, quiet down! How can anybody read over all that cheering?

There’s something missing from most Six Sigma implementations—a gap that, if left unattended, leads to wasted time and money, as well as the failure of the effort itself. This topic will help you make and maintain the business case for doing Six Sigma, since it will become integral to achieving the business’s objectives.

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Keeping it Real

Keeping it Real

Destroying Company Morale in One Easy Step

I was working with a client to create their business’s critical performance measures the other day, and one of the managers said, “We should set the target higher than we want it—you know, aim high to hit low.” This set off one of my rants, and I thought I would share it with you.

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Will Google Earn a Black Belt?

Will Google Earn a Black Belt?

And Make Black Belts Obsolete?

I read an article in Wired magazine the other day that got me to thinking about the relationship between statistics, engineering knowledge, and theory. The article claimed that with the era of massive data storage and analytical capabilities, the scientific concept of the “theory” was becoming obsolete. What implications does this have for people working with data to solve problems? Can we find solutions without a theory? Will Google obsolete the Black Belt?

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No News is NOT Good News

No News is NOT Good News

What your complaints process never told you

In the Six Sigma world, we give a lot of lip service to the importance of the customer; we even have an official name for it—voice of the customer, or VOC. The problem is that many businesses don’t really have a good system for giving the customer what they ask for, much less one for listening to what they say. If you have been into a retail store recently, you may wonder if anyone has a good system for that. So what should a good customer quality assurance (CQA) system look like?

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