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Blind Wine Part I: The Experiment

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 and plum flavors, with some notes of vanilla and leather.

The wine is poured and as Brutus swirls it in his glass and breathes in the aromas, he picks up some of the oak infused into the wine as it aged...

Where Did All the World Cup Goals Go? Find Out with a 2-Sample Poisson Rate Test

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 per game fell off and ended up being pretty similar to other recent World Cups.

What happened?

Comparing the Group Stage to the Knockout Stage

After 15 straight days of games in the group stage, there...

Two-Way ANOVA in Minitab 17

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 new version?  Shouldn’t the new version have more features instead of less? 

Two-Way ANOVA was removed from Minitab 17 because you can get the same output by using the General Linear Model option in...

Guest Post: Did Ma's Diabetes Get Cured by Back Surgery?

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 readings in Minitab Statistical Software.

I did it three times a day before meals...over weeks, then months, then years. At each doctor's appointment I would take in her 'book' of readings, and I would...

Bar Chart: Where to Start?

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 are surprised at how many different options are presented when you go to Graph > Bar Chart... in Minitab. There are, in fact, 14 different options based on 1) what you want your final graph to...

Can I Just Delete Some Values to Reduce the Standard Variation in My ANOVA?

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 deviation is low?

In other words, this person wanted a way to automatically eliminate certain values to lower the standard deviation.

Fortunately, Minitab 17 does not have the functionality that this person was...

Using Probability Plots to Understand Laser Games Scores

There is more than just the p value in a probability plot—the overall graphical pattern also provides a great deal of useful information. Probability plots are a powerful tool to better understand your data.

In this post, I intend to present the main principles of probability plots and focus on their visual interpretation using some real data.

In probability plots, the data density distribution is transformed into a linear plot. To do this, the cumulative density function (the so-called CDF, cumulating all probabilities below a given threshold) is used (see the graph below). For a normal...

The 6 coolest tools on Minitab's toolbars

Toolbars are there to make your life easier, but if you don’t take the time to hover over each button and wait for a description, it’s pretty easy to never know that there’s a faster way to do something.

The toolbars in Minitab Statistical Software include some pretty nifty shortcuts. Here are my favorite 6:

StatGuide

As soon as you have results in Minitab, the StatGuide button becomes active on your toolbar. Click the button, and the StatGuide opens directly to guidance for the analysis that you’re looking at. Minitab saves you the time you would have spent looking for information about your...

The Five Coolest Things You Can Do When You Right-click a Graph in Minitab Statistical Software

Minitab graphs are powerful tools for investigating your process further and removing any doubt about the steps you should take to improve it. With that in mind, you’ll want to know every feature about Minitab graphs that can help you share and communicate your results effectively. While many ways to modify your graph are on the Editor menu, some of the best features become available when you right-click your graph.

Here are the five coolest things you can do when you right-click a graph in Minitab Statistical Software.

Send graph to...

Once your graph is ready for your report or presentation,...

An Unlikely Statistician: Florence Nightingale

Many of my close friends and family members are nurses, and I’ve noticed (via Facebook of course) that many recently celebrated National Nurses’ Week, which ran Tuesday, May 6 through Monday, May 12—the actual birthday of Florence Nightingale.

Florence Nightingale is known as the founder of modern nursing, but you might not know that she is also a celebrated statistician. When I started reading more about her contributions to statistics, I was surprised to find that she used statistics to not only learn more about how many people died during wartime, and why, but also as a way to visually...

Gage This or Gage That? How the Number of Distinct Categories Relates to the %Study Variation

We cannot improve what we cannot measure. Therefore, it is critical that we conduct a measurement systems analysis (MSA) before we start analyzing our data to make any kind of decisions.

When conducting an MSA for continuous measurements, we typically using a Gage R&R Study. And in these Gage R&R Studies, we look at output such as the percentage study variation (%Study Var, or %SV) and the Number of Distinct Categories (ndc) to assess whether our measurement system is adequate.

Looking at these 2 values to assess a measurement system often leads to questions like "Should I look at both values? ...

Dividing a Data Set into Training and Validation Samples

Adam Ozimek had an interesting post April 15th on the Modeled Behavior blog at Forbes.com. He observed that one of the advantages of big data is how easy it is to get test data to validate a model that you built from sample data.

Ozimek notes that he is “for the most part a p-value checking, residual examining, data modeling culture economist,” but he’s correct to observe that if you can test your model on real data, then you should.

What I’ll describe is certainly not the only way to divide data in Minitab Statistical Software. Still, I think it’s pretty good if I do say so myself. Want...

Creating a Custom Report using Minitab, part 2

Now that you’ve seen how to automatically import data and run analyses in my previous post, let’s create the Monthly Report!

I will be using a Microsoft Word Document (Office 2010) and adding bookmarks to act as placeholders for the Graphs, statistics, and boilerplate conclusions.

Let’s go through the steps to accomplish this:

  • Open up an existing report that you have previously created in Microsoft Word.
  • Highlight a section of the document where you would like to place the created Minitab graph or statistic.
  • Go to the Insert tab, click the Bookmark link, and type in the name of what you will be...

Re-analyzing Wine Tastes with Minitab 17

In April 2012, I wrote a short paper on binary logistic regression to analyze wine tasting data. At that time, François Hollande was about to get elected as French president and in the U.S., Mitt Romney was winning the Republican primaries. That seems like a long time ago…

Now, in 2014, Minitab 17 Statistical Software has just been released. Had Minitab 17, been available in 2012, would have I conducted my analysis in a different way?  Would the results still look similar?  I decided to re-analyze my April 2012 data with Minitab 17 and assess the differences, if there are any.

There were no...

What Can Classical Chinese Poetry Teach Us About Graphical Analysis?

A famous classical Chinese poem from the Song dynasty describes the views of a mist-covered mountain called Lushan.

The poem was inscribed on the wall of a Buddhist monastery by Su Shi, a renowned poet, artist, and calligrapher of the 11th century.

Deceptively simple, the poem captures the illusory nature of human perception.
 

   Written on the Wall of West Forest Temple

                                      --Su Shi
 
  From the side, it's a mountain ridge.
  Looking up, it's a single peak.
  Far or near, high or low, it never looks the same.
  You can't know the true face of Lu Mountain
  When...

ITEA Sneak-Peek: The Great Escape from Foam Defects

The 2014 ASQ World Conference on Quality and Improvement is coming up in early May in Dallas, and this year’s International Team Excellence Award Process (ITEA) will also come to a close at the conference, as winners from the finalist teams will be chosen for ASQ gold, silver, or bronze-level statuses.

What’s ITEA?

The annual ASQ ITEA process celebrates the accomplishments of quality improvement teams from a broad spectrum of industries from around the world. The ITEA is the only international team recognition process of its kind in the United States, and since 1985, more than 1,000 teams from...

Introducing the Bubble Plot

When you're evaluating a dataset, graphical analysis can be very important. While an analysis like a regression or ANOVA can be backed up by numbers, being able to visualize how your dataset is behaving can be even more convincing than a group of p-values—especially to those who aren’t trained in statistics.

For example, let’s look at a few variables we think may be correlated. In this specific example, we will take the Unemployment Rate and the Crime Rate for each state in the U.S. We have 3 columns of data in Minitab: C1, which contains the State Name; C2, which contains the Crime Rate; and...

Using Statistics to Show Your Boss Process Improvements

Ughhh... your process is producing some parts that don't meet your customer's specifications! Fortunately, after a little hard work, you find a way to improve the process.

However, you want to perform the appropriate statistical analysis to back up your findings and make it easier to explain the process improvements to your boss. And it's important to remember that your boss is much like the boss in Eston's posts -- he's not too familiar with statistics, so you'll have to take it slow and show lots of "visual aids" in your explanation. How should you begin? 

Enter before-and-after process...

How to Handle Extreme Outliers in Capability Analysis

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 and non-normal distributions are not good approaches for data that contain extreme outliers.

As an example, the four graphs below show distribution fits for a dataset with 99 values simulated from a...

Using nonparametric analysis to visually manage durations in service processes

My main objective is to encourage greater use of statistical techniques in the service sector and present new ways to implement them.

In a previous blog, I presented an approach you can use  to identify process steps that may be improved in the service sector (quartile analysis). In this post I'll show how nonparametric distribution analysis may be implemented in the service sector to analyze durations until a task is completed.

Knowing how much time you need to complete a task may be very useful when assessing process efficiency, and is an important factor in many businesses.

Consider a...