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Tips and Techniques for Statistics and Quality Improvement

Blog posts and articles about using Minitab software in quality improvement projects, research, and more.

In his post yesterday, my colleague Jim Colton applied binary logistic regression to data on the current ebola virus outbreak in Guinea, Liberia, and Sierra Leone, and revealed that, horrific as it is, this outbreak actually appears to have a lower death rate than some earlier ones.  He didn't address the potential for a global ebola pandemic, but over the last few days more than enough leading... Continue Reading
The current Ebola outbreak in Guinea, Liberia, and Sierra Leone is making headlines around the world, and rightfully so: it's a frightening disease, and last week the World Health Organization reported its spread is outpacing their response. Nearly 900 of  the more than 1,600 people infected during this outbreak have died, including some leading medical professionals trying to stanch the... Continue Reading
by Iván Alfonso, guest blogger I'm a huge fan of hot cakes—they are my favorite dessert ever. I’ve been cooking them for over 15 years, and over that time I’ve noticed many variation in textures, flavor, and thickness. Personally, I like fluffy pancakes. There are many brands of hotcake mix on the market, all with very similar formulations. So I decided to investigate which ingredients and inputs... Continue Reading
If you teach statistics or quality statistics, you’re probably already familiar with the cuckoo egg data set. The common cuckoo has decided that raising baby chicks is a stressful, thankless job. It has better things to do than fill the screeching, gaping maws of cuckoo chicks, day in and day out. So the mother cuckoo lays her eggs in the nests of other bird species. If the cuckoo egg is similar... Continue Reading
The calendar just flipped to August, meaning it’s time to get ready for fantasy football season! As you prepare for your draft, you will no doubt be looking at all sorts of rankings. But when the season is over, do you ever go back and see how accurate those rankings were? And are rankings for some positions more accurate than others? Well that’s exactly what we’re going to find out! I went back... Continue Reading
Last time, we went over Bar Charts you could create from Counts of Unique Values. However, sometimes you want to convey more information than just simple counts. For example, you could have a number of parts from different models. The number of occurrences themselves don't offer much value, so you may want a chart displaying the means, sums, or even standard deviations of the different parts.... Continue Reading
In Part I, Part II, and Part III we shared our experiment, the survey results, and the experimental results. To wrap things up, we're going to see if the survey results tied to the experimental results in any meaningful way... First, we look at whether self-identified knowledge correlated to the total number of correct appraisals: We have no evidence of a relationship (p = 0.795).  So we'll look... Continue Reading
In Part I and Part II we learned about the experiment and the survey, respectively. Now we turn our attention to the results... Our first two participants, Danielle and Sheryl, enter the conference room and are given blindfolds as we explain how the experiment will proceed.  As we administer the tasting, the colors of the wine are obvious but we don't know the true types, which have been masked... Continue Reading
Everyone loves a Pareto chart. That is, everyone who knows that Pareto charts are a type of bar chart ordered by bar size to help you to determine which bars comprise the vital few that you care about and which are the trivial many that you don't care about. Pareto charts are a great tool for communicating where the largest gains can be made as you focus your improvement efforts. Since I love... Continue Reading
In Blind Wine Part I, we introduced our experimental setup, which included some survey questions asked ahead of time of each participant. The four questions asked were: On a scale of 1 to 10, how would you rate your knowledge of wine? How much would you typically spend on a bottle of wine in a store? How many different types of wine (merlot, riesling, cabernet, etc.) would you buy regularly (not as... Continue Reading
Already relaxed on his first day in Napa, Brutus and his wife Suzy decide to visit their favorite winery just before lunch to taste their new Cabernet Sauvignon. The owner recognizes them as they walk in the door and immediately seats them on the patio overlooking the vineyard. Two glasses appear, and as the owner tells them about the new Cabernet, Brutus prepares for an onslaught of blackberry... Continue Reading
A few weeks ago I looked at the number of goals that were being scored in the World Cup. At the time there were 2.9 goals per game, which was the highest since 1970. Unfortunately for spectators who enjoyed the higher scoring goals, this did not last. By the end, the average had fallen to 2.7 goals per game, the same amount scored in the 1998 World Cup. After such a high-scoring start, the goals... Continue Reading
After upgrading to the latest and greatest version of our statistical software, Minitab 17, some users have contacted tech support to ask "Wait a minute, where is that Two-Way ANOVA option in Minitab 17?"  The answer is that it’s not there. That’s right! The 2-Way ANOVA option that was available in Minitab 16 and prior versions was removed from Minitab 17.Why would this feature be removed from the... Continue Reading
The Minitab Fan section of the Minitab blog is your chance to share with our readers! We always love to hear how you are using Minitab products for quality improvement projects, Lean Six Sigma initiatives, research and data analysis, and more. If our software has helped you, please share your Minitab story, too! Once my Mom was diagnosed with Diabetes Type II, I began to track her blood sugar... Continue Reading
Did you know that this year the American Statistical Association (ASA) is celebrating its 175th anniversary? That’s a pretty significant birthday! On the ASA’s 175thanniversary webpage, they publish blog posts periodically that cover ASA happenings, such as anniversary events and celebrations, as well as interesting tidbits about the organization. Recently, they published a post covering the... Continue Reading
There’s a lot going on in the world, so you might not have noticed that the Organization for Economic Development (OECD) released their new set of health statistics for member nations. On the OECD website, you can now download the free data series for 2014. (Be aware that “for 2014” means that the organization has a pretty good idea about what happened in 2012.) Of course, there’s nothing more fun... Continue Reading
Whether you’re just learning statistics or you're already using data analysis on the job, there are not many tools more straightforward than a bar chart. Bar charts are effective at getting across their message, and are used in a diverse number of fields, from service quality to pharmaceuticals to manufacturing. However, I’ve noticed recently that a lot of customers looking to create a bar chart... Continue Reading
The Six Sigma students at Rose-Hulman Institute of Technology are at it again! A few months back, we blogged about the Six Sigma project they did to reduce food waste at the on-campus dining center. This time, the students—lead by Dr. Diane Evans, Six Sigma black belt and associate professor of mathematics at Rose-Hulman—are performing a Lean Six Sigma project to reduce the amount of recycling... Continue Reading
We received the following question via social media recently: I am using Minitab 17 for ANOVA. I calculated the mean and standard deviation for these 15 values, but the standard deviation is very high. If I delete some values, I can reduce the standard deviation. Is there an option in Minitab that will automatically indicate values that are out of range and delete them so that the standard... Continue Reading
Previously, I’ve written about when to choose nonlinear regression and how to model curvature with both linear and nonlinear regression. Since then, I’ve received several comments expressing confusion about what differentiates nonlinear equations from linear equations. This confusion is understandable because both types can model curves. So, if it’s not the ability to model a curve, what isthe... Continue Reading