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Logistic Regression

Blog posts and articles about the statistical method called Logistic Regression and its use in quality improvement projects.

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
If betting wasn't allowed on horse racing, the Kentucky Derby would likely be a little-known event of interest only to a small group of horse racing enthusiasts. But like the Tour de France, the World Cup, and the Masters Tournament, even those with little or no knowledge of the sport in general seem drawn to the excitement over its premier event—the mint juleps, the hats...and of course,... Continue Reading
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 Softwarehas just been released. Had Minitab 17, been available in 2012, would have I... Continue Reading
Back in November, I wrote about why running the football doesn’t cause you to win games in the NFL. I used binary logistic regression to look at the relationship between rush attempts (both by the lead rusher and by the team) and wins. The results showed that the model for rush attempts by the lead rusher and wins fit the data poorly. But the model for team rush attempts and wins did fit the data... Continue Reading
We released Minitab 17 Statistical Software a couple of days ago. Certainly every new release of Minitab is a reason to celebrate. However, I am particularly excited about Minitab 17 from a data analyst’s perspective.  If you read my blogs regularly, you’ll know that I’ve extensively used and written about linear models. Minitab 17 has a ton of new features that expand and enhance many types of... Continue Reading
I’ve written a number of blog posts about regression analysis and I think it’s helpful to collect them in this post to create a regression tutorial. I’ll supplement my own posts with some from my colleagues. This tutorial covers many aspects of regression analysis including: choosing the type of regression analysis to use, specifying the model, interpreting the results, determining how well the... Continue Reading
I know we lost by 2 touchdowns, but if only you had given Peterson 3 more carries we would have won! Last week, ESPN ran an article about why the running game still matters. They used statistics to show that the more you run the football in the NFL, the more likely you are to win the game. Specifically, if you have a running back who gets at least 20 carries, you win about 70% of the... Continue Reading
As Halloween is almost here, I'm ready to check out some Halloween statistics. You can have a lot of fun with Minitab on Halloween. The National Retail Foundation (NRF) released the results of their Halloween Consumer Spending Survey last month. The basics are easy to summarize: Because we have Minitab, we can dig a little deeper into the data. The NRF gives some information about the proportion... 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
Here at Minitab we have a quite a few coffee drinkers.  From personal observation, it seemed as if people who are more outgoing are the ones doing most of the coffee drinking, while people who are less outgoing seem to opt for tea.  I’d noticed this over a period of time, and eventually decided to investigate. To test out my hypothesis, I decided to pester some of my coworkers by asking them to... Continue Reading
Human resources might not be a business area where you’d typically expect to conduct a Six Sigma project. However, Jeff Parks, Lean Six Sigma master black belt, found the opportunity to apply Six Sigma to human resources while leading quality improvement efforts at a large manufacturer of aerospace engine parts. The manufacturer was suffering from high employee attrition, or turnover, and struggled... 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
Yesterday, I presented a model that uses Dow Jones data to predict the winner in Presidential elections that have an incumbent. Today, I test a model that uses S&P 500 data. (Here are the data for today's blog that you can use in Minitab Statistical Software.) Model 2: The Three Month Change in the S&P 500 The second model is presented by Sam Stovall, Chief Equity Strategist at S&P Capital IQ in his... Continue Reading
You may have read about statistical models that claim to predict the outcome of the upcoming Presidential election. It’s easy to imagine that these models are complicated and contain many demographic, sociological, economic, and political factors. However, I was surprised to read in an article that two simple models supposedly generate accurate predictions. Both of these models use stock market... Continue Reading
Do you like checking out old yearbooks for photos and to see how the appearance of you or your friends may have changed over the years? In honor of Minitab Statistical Software’s 40th Anniversary, we dug through our own past to see how the "our look"  has changed since 1972. Check out how Minitab software packaging has evolved into what we know today: The very beginning - 1972 The first version of... Continue Reading
In my last blog, we looked at how a single data entry error can cruelly sabotage your statistical analysis. And if that doesn't scare you silly, maybe this will. The frequency of data entry errors can be as high as 27%, even when using the conservative "double-entry" method to record each data value twice.So what can you do? Besides make offerings to appease Ate, the ancient Greek goddess of... Continue Reading
In honor of the 100th anniversary of the sinking of the Titanic, we recently posted a dataset on the passengers aboard the ship that included Class (coach or first), Gender (female or male), Age, and Status (survived or died).  From Age an additional column was created indicating Child (17 years or younger) or Adult (18 years or older). In an earlier post, we showed how survival rates could be... Continue Reading
St. Patrick’s Day is just around the corner, and maybe you’ve found yourself thinking about four-leaf clovers and trying to find one yourself. According to Irish tradition, those who find a four-leaf clover are destined for good luck, as each leaf in the clover symbolizes good omens for faith, hope, love, and luck for the finder. A lesser-known fact about four-leaf clovers is that they aren’t the... Continue Reading