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Use a Line Plot to Show a Summary Statistic Over Time

If you’re already a strong user of Minitab Statistical Software, then you’re probably familiar with how to use bar charts to show means, medians, sums, and other statistics. Bar charts are excellent tools, but traditionally used when you have a categorical variable on your x-axis. When you want to plot statistics with a continuous variable on your y-axis, look no further than Minitab’s line plots. Line plots are particularly well-suited for when you want to plot a statistic like the sum or the mean over time.

I like to illustrate Minitab with data about pleasant subjects: poetry, candy, and...

How Accurate are Fantasy Football Rankings? Part II

Previously, we looked at how accurate fantasy football rankings were for quarterbacks and tight ends. We found out that rankings for quarterbacks were quite accurate, with most of the top-ranked quarterbacks in the preseason finishing in the top 5 at the end of the season. Tight end rankings had more variation, with 36% of the top 5 preseason tight ends (over the last 5 years) actually finishing outside the top 10!

Now it’s time to move our attention to the running backs and wide receivers. Just like before, I went back the previous 5 seasons and found ESPN’s preseason rankings. For each...

Using the G-Chart Control Chart for Rare Events to Predict Borewell Accidents

by Lion "Ari" Ondiappan Arivazhagan, guest blogger

In India, we've seen this story far too many times in recent years:

Timmanna Hatti, a six-year old boy, was trapped in a 160-feet borewell for more than 5 days in Sulikeri village of Bagalkot district in Karnataka after falling into the well. Perhaps the most heartbreaking aspect of the situation was the decision of the Bagalkot district administration to stop the rescue operation because the digging work, if continued further, might lead to collapse of the vertical wall created by the side of the borewell within which Timmanna had struggled for...

How Deadly Is this Ebola Outbreak?

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 outbreak's spread. And yesterday, one of the American doctors who contracted the disease arrived back in the U.S. for treatment.

Many sources state that Ebola virus outbreaks have a case fatality rate of up to...

Cuckoo for Quality: A Birdseye View of a Classic ANOVA Example

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 enough to the eggs of the host bird, in size and color pattern, the host bird may be tricked into incubating the egg and raising the hatchling. (The cuckoo can then fly off to the French Riviera, or...

“You’ve got a friend” in Minitab Support

I caught the end of Toy Story over the weekend, which is definitely one of my all-time favorite children’s movies. Now—unfortunately or fortunately—I can’t get Randy Newman's theme song,“You’ve Got a Friend in Me,” out of my head!

It's also got me thinking about the nature of friendship, and how "best friends forever" are supposed to always be there when you need them. And, not to get too maudlin about it, but just like Woody and Buzz eventually realize their friendship, all of us hope the professionals who use our software also realize that “you’ve got a friend” in Minitab.

Now what do I mean...

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...

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...

Guest Post: Analysis of Road Accidents in Hyderabad

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!

 

An Analysis of Road Accidents in Hyderabad, India

The data taken for this study is obtained from the official website of Hyderabad Traffic Police (http://www.htp.gov.in/Default.htm). Also note that the data for 2014 covers only the period until April.

Reviewing the time series plot I...

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,...

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...

Common Statistical Mistakes You Should Avoid

It's all too easy to make mistakes involving statistics. Powerful statistical software can remove a lot of the difficulty surrounding statistical calculation, reducing the risk of mathematical errors—but  correctly interpreting the results of an analysis can be even more challenging. 

No one knows that better than Minitab's technical trainers. All of our trainers are seasoned statisticians with years of quality improvement experience. They spend most of the year traveling around the country (and around the world) to help people learn to make the best use of Minitab software for analyzing data...

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? ...

When Will I Ever See This Statistics Software Again?

Minitab Statistical Software was born out of a desire to make statistics easier to learn: by making the calculations faster and easier with computers, the trio of educators who created the first version of Minitab sought to free students from intensive computations to focus on learning key statistical concepts. That approach resonated with statistics instructors, and today Minitab is the standard for teaching and learning statistics at more than 4,000 universities all over the world.

But many students seem to believe Minitab is used only in education. Search Twitter for "Minitab," and you're...

"Hidden Helpers" in Minitab Statistical Software

Minitab Statistical Software offers many features that can save you time and effort when you’re learning statistics or analyzing data. However, when we demonstrate many of these short cuts, tools, and capabilities at shows and events, we find that even some longtime users aren’t aware of them.

I asked members of our sales team and technical support staff to list some of Minitab’s most helpful, yet frequently overlooked features. How many do you use—or want to start using?

Can You Repeat That?

Frequently, you’ll need to modify or re-run some part of an analysis you conducted. You can easily return...

Hockey Penalties, Fans Booing, and Independent Trials

We’re in the thick of the Stanley Cup playoffs, which means hockey fans are doing what seems to be every sports fan's favorite hobby...complaining about the refs! While most complaints, such as “We’re not getting any of the close calls!” are subjective and hard to get data for, there's one question that we should be able to answer objectively with a statistical analysis: Are hockey penalties independent trials? That is, does the team that the next penalty will be called on depend on the team that any previous penalties were called on?

Think of flipping a coin. Even if it comes up heads 10 times...

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...

Did Welch’s ANOVA Make Fisher's Classic One-Way ANOVA Obsolete?

One-way ANOVA can detect differences between the means of three or more groups. It’s such a classic statistical analysis that it’s hard to imagine it changing much.

However, a revolution has been under way for a while now. Fisher's classic one-way ANOVA, which is taught in Stats 101 courses everywhere, may well be obsolete thanks to Welch’s ANOVA.

In this post, I not only want to introduce you to Welch’s ANOVA, but also highlight some interesting research that we perform here at Minitab that guides the implementation of features in our statistical software.

One-Way ANOVA Assumptions

Like any...

Equivalence Testing for Quality Analysis (Part I): What are You Trying to Prove?

With more options, come more decisions.

With equivalence testing added to Minitab 17, you now have more statistical tools to test a sample mean against target value or another sample mean.

Equivalence testing is extensively used in the biomedical field. Pharmaceutical manufacturers often need to test whether the biological activity of a generic drug is equivalent to that of a brand name drug that has already been through the regulatory approval process.

But in the field of quality improvement, why might you want to use an equivalence test instead of a standard t-test?

Interpreting Hypothesis...