Jim Colton

Jim Colton, former technical training specialist at Minitab, wrote for the Minitab Blog from 2013-2016. 

How many samples do you need to be “95% confident that at least 95%—or even 99%—of your product is good? The answer depends on the type of response variable you are using, categorical or continuous. The type of response will dictate whether you 'll use: Attribute Sampling: Determine the sample size for a categorical response that classifies each unit as Good or Bad (or, perhaps, In-spec or... Continue Reading
Have you ever had a probability plot that looks like this? The probability plot above is based on patient weight (in pounds) after surgery minus patient weight (again, in pounds) before surgery. The red line appears to go through the data, indicating a good fit to the Normal, but there are clusters of plotting points at the same measured value. This occurs on a probability plot when there are many... Continue Reading
There's more data available today than ever before, and with statistical software such as Minitab it only takes a couple of seconds to get some significant insights, whether it concerns how to make your business run better or national politics.  For instance, if we look back at the last 9 presidential elections (1980 to 2012), there are some interesting correlations between the percent of state... Continue Reading
The 2014-15 NFL season is only days away, and fans all over the country are planning their fall weekends accordingly. In this post, I'm going to use data analysis to answer some questions related to ticket prices, such as: Which team is the least/most expensive to watch at home?  Which team is the least/most expensive to watch on the road?  If you are thinking of a road trip, which stadiums offer... Continue Reading
Transformations and non-normal distributions are typically the first approaches considered when the when the Normality test fails in a capability analysis. These approaches do not work when there are extreme outliers because they both assume the data come from a single common-cause variation distribution. But because extreme outliers typically represent special-cause variation, transformations... Continue Reading
We're frequently asked whether Minitab has been validated by the U.S. Food and Drug Administration (FDA) for use in the pharmaceutical and medical device industries. Minitab does extensive testing to validate our software internally, but Minitab’s statistical software is not—and cannot be—FDA-validated out-of-the-box. Nobody's can. It is a common misconception that software vendors can go through a... Continue Reading
In the sports world, it is generally accepted that the NHL players who participate in the Olympics (approximately 20%) put their NHL team at a disadvantage for the remainder of the season. The NHL season does stop during the Olympic Games, but the thought is that the best NHL players leave their team to play the extra games, which will tire them out for the remainder of the NHL regular season and... Continue Reading
All measurements are rounded to some degree. In most cases, you would not want to reject normality just because the data are rounded. In fact, the normal distribution would be a quite desirable model for the data if the underlying distribution is normal since it would smooth out the discreteness in the rounded measurements. Some normality tests reject a very high percentage of time due to rounding... Continue Reading
Even the best NHL goalies can get pulled several times each season. Do they really have cold streaks, or is a drop in save percentage on a given day part of normal random variation? My colleague Doug Gorman and I decided to find out using our favorite statistical software package.   Control Charts for Coaching Decisions We used a control chart approach to determine if coaching decisions to pull... Continue Reading
Minitab Statistical Software offers three tests for Normality: Anderson-Darling (AD), Ryan-Joiner (RJ), and Kolmogorov-Smirnov (KS). The AD test is the default, but is it the best test at detecting Non-Normality? Let's compare the ability of each of these normality tests to detect non-normal data under three different scenarios.  We'll use simulated data for each, but they reflect common... Continue Reading
The Pro Bowl is the National Football League’s version of an all-star team. In this blog post, I'll look at all the NFL draft picks from 1996 through 2008 and, using Minitab Statistical Software, model the probability of making it to at least one Pro Bowl based on draft order, the NFL team that drafted the player, the NCAA team the player came from, and the position of the player. I did not include... Continue Reading
I received my B.S. in applied statistics in 1992 from Rochester Institute of Technology (R.I.T) and my master's in applied statistics from R.I.T's Center for Quality and Applied Statistics in 1993. I also completed Ph.D. coursework at The University of Washington and The Ohio State University. While working towards my Statistics degrees, I further developed my industrial skills working at Xerox,... Continue Reading
Purchasing a used car can be stressful due to all the factors that need to be considered. Web sites such as www.cars.com provide you a wealth of information, but how do you navigate through it all to find the best deal? Minitab to the rescue. Once you narrow your choice down to a particular car model, such as an Acura TSX, the data from www.cars.com can be copied and pasted into Minitab. After some... Continue Reading