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Statistics

Blog posts and articles about statistical principles in quality improvement methods like Lean and Six Sigma.

The College Football Playoff technically doesn't start until December 31st, but in reality it started Saturday night in Indianapolis. The winner of the Big Ten Championship Game was in the playoff, while the loser was out. The stakes couldn't have been higher. So the competitors need to make sure they gain every advantage they can. And that's where 4th down decisions come in. With a lot of... Continue Reading
There are many reasons why a distribution might not be normal/Gaussian. A non-normal pattern might be caused by several distributions being mixed together, or by a drift in time, or by one or several outliers, or by an asymmetrical behavior, some out-of-control points, etc. I recently collected the scores of three different teams (the Blue team, the Yellow team and the Pink team) after a laser... Continue Reading

7 Deadly Statistical Sins Even the Experts Make

Do you know how to avoid them?

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P-values are frequently misinterpreted, which causes many problems. I won't rehash those problems here here since my colleague Jim Frost has detailed the issues involved at some length, but the fact remains that the p-value will continue to be one of the most frequently used tools for deciding if a result is statistically significant.  You know the old saw about "Lies, damned lies, and... Continue Reading
There was a lot at stake in the final week of Big Ten play this week. Three different games had an impact on not only the Big Ten Championship Game, but the College Football playoff as well. Unfortunately for the viewers, none of the games were really close in the 4th quarter. But that doesn't mean we can't analyze the 4th down decisions in the first 3 quarters and see whether the losing teams had... Continue Reading
‘Statistics’ is a rising star. Everywhere I turn, people are talking about data and the value of being able to analyze and act on it. As someone who’s been writing about that for years, I say it’s about time. Statistics is like a talented actress whose decades of appearing off Broadway have finally paid off. For years, her work has been enriching our lives without us knowing it. Statistics helps... Continue Reading
This week is the annual Thanksgiving holiday in the United States, a period where we are encouraged to eat turkey and cranberries, then consider the blessings in our lives before falling into a comfortable pre-football nap. That includes many of us here at Minitab.  Consequently, we won't have new posts for you over the next two days.  But one of the things I'm grateful for is having had the... Continue Reading
This past weekend in the Big Ten showed how being conservative on 4th down decisions can cost you a game. Ohio State punted on 4th and 1 three different times, while Penn State and Illinois both kicked field goals in the 4th quarter when they needed a touchdown to tie or take the lead. All three teams lost. Perhaps taking some advice from the 4th down calculator would have greatly benefited them! If... Continue Reading
Back when I was an undergrad in statistics, I unfortunately spent an entire semester of my life taking a class, diligently crunching numbers with my TI-82, before realizing 1) that I was actually in an Analysis of Variance (ANOVA) class, 2) why I would want to use such a tool in the first place, and 3) that ANOVA doesn’t necessarily tell you a thing about variances. Fortunately, I've had a lot more... Continue Reading
According to this article published on Food Tank, over 22 million pounds of food is wasted on college campuses each year. Now that’s a lot of food waste! Students all over the country are noticing excessive food waste at their schools and are starting programs to bring awareness and improve the problem. Naturally, many of these programs have roots in Lean Six Sigma. In one example, a group of... Continue Reading
We use statistics to arm ourselves with more information. That information allows us to make more informed decisions. And the sooner we can obtain this information, the better. For example, suppose one of your manufacturing machines starts to malfunction and makes your products out of spec. You don't want to wait until the product reaches customers before you discover this information. Then it's... Continue Reading
Did you ever wonder why statistical analyses and concepts often have such weird, cryptic names? One conspiracy theory points to the workings of a secret committee called the ICSSNN. The International Committee for Sadistic Statistical Nomenclature and Numerophobia was formed solely to befuddle and subjugate the masses. Its mission: To select the most awkward, obscure, and confusing name possible... Continue Reading
Control charts are a fantastic tool. These charts plot your process data to identify common cause and special cause variation. By identifying the different causes of variation, you can take action on your process without over-controlling it. Assessing the stability of a process can help you determine whether there is a problem and identify the source of the problem. Is the mean too high, too low,... Continue Reading
Last time I touched on the subject of the greatest Super Bowl quarterback, I promised a multivariate analysis considering several different statistics. Let’s get right to a factor analysis. Getting Ready for Factor Analysis One purpose of factor analysis is to identify underlying factors that you can’t measure directly. These factors explain the variation of many different variables in fewer... Continue Reading
Don't be a grumpy cat when something on your capability report doesn't smell right. After pressing that OK button to run your analysis, allow your inner cat to understand how and why certain statistics are being used. To help you along, here are some capability issues that customers have brought up recently. Cp is missing You’ve generated a capability analysis report with the Johnson transformation... Continue Reading
By Matthew Barsalou, guest blogger A problem must be understood before it can be properly addressed. A thorough understanding of the problem is critical when performing a root cause analysis (RCA) and an RCA is necessary if an organization wants to implement corrective actions that truly address the root cause of the problem. An RCA may also be necessary for process improvement projects; it is... Continue Reading
I have two young children, and I work full-time, so my adult TV time is about as rare as finding a Kardashian-free tabloid.  So I can’t commit to just any TV show. It better be a good one. I was therefore extremely excited when Netflix analyzed viewer data to find out at what point watchers get hooked on the first season of various shows. Specifically, they identified the episode at which 70% of... Continue Reading
4th and 1. It's a situation where the Big Ten 4th down calculator will never say to kick (unless, of course, it's the end of the game and a field goal will tie or take the lead). But what would it take to have the statistics suggest a punt? The key here is how far the punt travels. Last year the average Big Ten punt traveled about 40 yards. Using this value, in your own territory you'll score... Continue Reading
Easy access to the right tools makes any task easier. That simple idea has made the Swiss Army knife essential for adventurers: just one item in your pocket gives you instant access to dozens of tools when you need them.   If your current adventures include analyzing data, the Editor menu in Minitab 17 is just as essential. Minitab’s Dynamic Editor Menu Any job goes more smoothly when you have easy... Continue Reading