Patrick Runkel

Communicating statistical concepts quickly and clearly is just as critical as being able to calculate them, so I focus on quick, practical insights about statistics to help you make data-driven decisions. Continue Reading »

Boxers or briefs. Republican or Democrat. Yin or yang. Why is it that life often seems to boil down to two choices? Heck, it even happens when you open the Basic Stats menu in Minitab. You’ll see a choice between a 2-sample t-test and a paired t-test: Which test should you choose? And what’s at stake? Ask a statistician, and you might get this response: "Elementary, my dear Watson. Choose the 2-sample... Continue Reading
A t-test is one of the most frequently used procedures in statistics. But even people who frequently use t-tests often don’t know exactly what happens when their data are wheeled away and operated upon behind the curtain using statistical software like Minitab. It’s worth taking a quick peek behind that curtain. Because if you know how a t-test works, you can understand what your results really mean.... Continue Reading
Unless you’re 3 years old, you probably can’t have things just the way you want them all the time.   You can’t always have peanut butter and ranch dressing on your toast. Or ketchup on your pineapple. Or sugar sprinkles on your peas. But there is one small arena in life over which you can still exert your control.  Tools > Options in Minitab's statistical softwareallows you to change selected default... Continue Reading
  “Shall I compare thee to a standard normal distribution?   Thou art more symmetric and more bell-shaped…”  — Melvin Shakespeare (William’s lesser-known statistician brother) The Greek philosopher Aristotle believed that symmetry was one of the primary elements of the universal ideal of beauty. Over 2000 years later, emerging research seems to bear him out.  Studies suggest we tend to be more... Continue Reading
Using a Survey of Aquatic Bugs to Estimate Stream Quality As we click, flip, and scroll through hundreds of sites and channels, cruising for our daily dose of e-thrills, it’s easy to forget there’s a beautiful, wild, creative universe right in our backyards. I had the chance to experience a tiny part of that universe on a recent Saturday afternoon, when a couple of friends, Yolanda and Monika, asked... Continue Reading
by Patrique Roonquel, guest blogger Institut Sacre Bleu I enjoy using Minitab Statistical Software to uncover the vast causal relationships unfolding in the universe all around me.  What kind of novel things have I proven with Minitab? Almost anything you can imagine, mon petite shoe. For example, the fitted line plot below clearly shows one thing:  it’s time for our political parties to stop all the... Continue Reading
Has it happened to you?   You organize a brainstorming session to begin analyzing your process. At the kick-off meeting, several people sit with arms crossed, lips pursed, eyes cast downward. Frequently, they’re the ones who’ve worked at the process for most of their professional lives. “Here we go again. Wasting time to prove the obvious,” their faces say. “I’ve done my job for years. You’re not... Continue Reading
If the title of this post made you think you’d be reading about Abraham Lincoln and Tyra Banks, you’re only half right.  A few weeks ago, statistician and journalist Nate Silver published an interesting post  on how U.S. presidents are ranked by historians. Silver showed that the percentage of electoral votes that a U.S. president receives in his 2nd term election serves as a rough predictor of... Continue Reading
  Lionel Loosefit has been hauled to court for violating the assumptions of regression analysis. On the last day of the trial, the prosecution and defense present their closing arguments. And the fate of Mr. Loosefit is decided by judge and jury... The Prosecution's Summary Prosecutor: Ladies and gentlemen, we’ve presented a slew of evidence in this trial. You’ve seen, with your own eyes, every... Continue Reading
Lionel Loosefit has been hauled to court for violating the assumptions of linear regression. On Day 3 of the trial, the court examines the allegation that the residuals in Mr. Loosefit's model exhibit nonconstant variance. The defendant’s mother, Mrs. Lottie Loosefit, has taken the stand on behalf of her son. Defense Attorney: So, Mrs. Loosefit, from what you’ve described to us, your son, Lionel,... Continue Reading
Recap: Lionel Loosefit has been arrested and hauled to court for violating the assumptions of regression analysis. In the previous court session, the prosecution presented evidence to show that the errors in Mr. Loosefit’s model were not normally distributed. Today, the prosecution addresses the second alleged violation: namely, that the errors in the defendant’s regression model are not... Continue Reading
Bailiff: All Rise. The Honorable Judge Lynn E. R. Peramutter presiding.Judge: Please be seated. Bailiff, please read the charges.Bailiff: Your honor, this is the case of the State vs. Lionel Loosefit. The defendant is charged with creating a model that violated the legal requirements for regression. The infractions include: Producing grossly nonnormal errors Producing errors that lack independence Exh... Continue Reading
Whenever something suddenly fell apart, my grandfather used to exclaim “Down goes the meat house!” I don’t know where that expression came from—as a child I often pictured a flabby house of raw meat caving in on itself. (This was decades before Lady Gaga made wearing raw meat dresses...uh...er... fashionable?) My grandfather’s expression still pops into my head when I think about a probit analysis.... Continue Reading
Juicy, butter roasted turkey. Steaming mashed potatoes. Tangy cranberry relish. Delicious candied sweet potatoes. Creamy green bean casserole. Sweet and airy corn bread. Silken pumpkin pie. The traditional Thanksgiving menu has so many mouth-watering dishes on the table, you don’t know where to start. If you savor statistics as much as food, you might feel similarly as you gaze at all of the delicious ... Continue Reading
It’s been a grueling election campaign for Senator William Overstate, or Will Overstate, as he is known by his constituents. Senator Overstate has been running his re-election campaign on a single issue: to make Election Day a national holiday. That sounds good to me! The senator argues that it's difficult for many people to get to the polls on election day because of work—especially those who work ... Continue Reading
So what stops eligible U.S. voters from showing up at the polls on election day?  I’m not going to be able to tease out all the possible factors associated with variability in voter turnout in one blog post.  But you can often be forgiven in statistics if you clearly state at the onset that your main objective is a preliminary exploration rather than a final, conclusive analysis. So let’s explore. Do... Continue Reading
This Tuesday is the big day. If you think I mean National Saxophone Day, please remember to put your sax down on November 6 and go vote! Otherwise, voter turnout for the election will be nothing to toot your horn over. As it is, the percentage of  people who turn up at the polls to vote is much lower in the U.S. than in many other democracies around the world. Or is it?  Surprisingly, a lot depends... Continue Reading
If you walk along an open field in central Pennsylvania in September, blaze orange is often the first sign of approaching fall you'll see. And it happens before the leaves even begin to turn color. The annual migration of millions of monarch butterflies in North America is one of the great wonders of nature. Every autumn, these delicate beauties flutter from as far north as Canada to their... Continue Reading
You know the famous proverb: "Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime." It's especially true when you're casting your line for statistics. When I first started using Minitab Statistical Software, it was daunting trying to learn all of its analysis capabilities. There are hundreds of commands in the Stat menu alone! Eventually, I found that... Continue Reading
 Sheriff Taylor: Remember the talk we had awhile back about Pp?Barney: Keep talking like a potty mouth, Andy, and Aunt Bea’s going to wash your mouth out with soap!Sherriff Taylor (sighs): So you remember that Pp is the ratio of the specification spread to—Barney (interrupts): —the process spread! Yeah, yeah, I got all that. And the smaller your car (process spread), relative to its parking space... Continue Reading