Understanding Statistics

How to Avoid Overfitting Your Regression Model

Eston Martz 31 August, 2017

Overfitting a model is a real problem you need to beware of when performing regression analysis. An overfit model result in misleading regression coefficients, p-values, and R-squared statistics. Nobody wants that, so let's examine what overfit models are, and how to avoid falling into the overfitting trap. Put simply, an overfit model is too complex for the data you're analyzing. Rather than... Continue Reading

The Easiest Way to Do Multiple Regression Analysis

Eston Martz 29 August, 2017

Maybe you're just getting started with analyzing data. Maybe you're reasonably knowledgeable about statistics, but it's been a long time since you did a particular analysis and you feel a little bit rusty. In either case, the Assistant menu in Minitab Statistical Software gives you an interactive guide from start to finish. It will help you choose the right tool quickly, analyze your data... Continue Reading

Controls Charts Are Good for So Much More than SPC!

Eston Martz 24 August, 2017

Control charts take data about your process and plot it so you can distinguish between common-cause and special-cause variation. Knowing the difference is important because it permits you to address potential problems without over-controlling your process. Control charts are fantastic for assessing the stability of a process. Is the process mean unstable, too low, or too high? Is observed... Continue Reading

What's the Difference between Confidence, Prediction, and Tolerance Intervals?

Eston Martz 22 August, 2017

In statistics, as in life, absolute certainty is rare. That's why statisticians often can't provide a result that is as specific as we might like; instead, they provide the results of an analysis as a range, within which the data suggest the true answer lies. Most of us are familiar with "confidence intervals," but that's just of several different kinds of intervals we can use to characterize the... Continue Reading

5 More Critical Six Sigma Tools: A Quick Guide

Eston Martz 10 August, 2017

The Six Sigma quality improvement methodology has lasted for decades because it gets results. Companies in every country around the world, and in every industry, have used this logical, step-by-step method to improve the quality of their processes, products, and services. And they've saved billions of dollars along the way. However, Six Sigma involves a good deal of statistics and data analysis,... Continue Reading

5 Critical Six Sigma Tools: A Quick Guide

Eston Martz 8 August, 2017

Six Sigma is a quality improvement method that businesses have used for decades—because it gets results. A Six Sigma project follows a clearly defined series of steps, and companies in every industry in every country around the world have used this method to resolve problems. Along the way, they've saved billions of dollars. But Six Sigma relies heavily on statistics and data analysis, and many... Continue Reading

3 Keys to Getting Reliable Data

Eston Martz 1 August, 2017

Can you trust your data? That's the very first question we need to ask when we perform a statistical analysis. If the data's no good, it doesn't matter what statistical methods we employ, nor how much expertise we have in analyzing data. If we start with bad data, we'll end up with unreliable results. Garbage in, garbage out, as they say. So, can you trust your data? Are you positive?... Continue Reading

How to Eliminate False Alarms on P and U Control Charts

Eston Martz 25 July, 2017

All processes have variation, some of which is inherent in the process, and isn't a reason for concern. But when processes show unusual variation, it may indicate a change or a "special cause" that requires your attention. Control charts are the primary tool quality practitioners use to detect special cause variation and distinguish it from natural, inherent process variation. These charts graph... Continue Reading

Sealing Up Patient Safety with Monte Carlo Simulation

Eston Martz 14 July, 2017

If you have a process that isn’t meeting specifications, using the Monte Carlo simulation and optimization tools in Companion by Minitab can help. Here’s how you, as an engineer in the medical device industry, could use Companion to improve a packaging process and help ensure patient safety. Your product line at AlphaGamma Medical Devices is shipped in heat-sealed packages with a minimum seal... Continue Reading

Making Steel Even Stronger with Monte Carlo Simulation

Eston Martz 19 June, 2017

If you have a process that isn’t meeting specifications, using Monte Carlo simulation and optimization can help. Companion by Minitab offers a powerful, easy-to-use tool for Monte Carlo simulation and optimization, and in this blog we'll look at the case of product engineers involved in steel production for automobile parts, and how they could use Companion to improve a process. The tensile... Continue Reading

Need to Validate Minitab per FDA Guidelines? Get Minitab's Validation Kit

Eston Martz 16 June, 2017

Last week I was fielding questions on social media about Minitab 18, the latest version of our statistical software. Almost as soon as the new release was announced, we received a question that comes up often from people in pharmaceutical and medical device companies: "Is Minitab 18 FDA-validated?" How Software Gets Validated That's a great question. To satisfy U.S. Food and Drug Administration (FDA)... Continue Reading

A Swiss Army Knife for Analyzing Data

Eston Martz 14 June, 2017

Easy access to the right tools makes any task easier. That simple idea has made the Swiss Army knife essential for adventurers: just one item in your pocket gives you instant access to dozens of tools when you need them. If your current adventures include analyzing data, the multifaceted Editor menu in Minitab Statistical Software is just as essential. Minitab’s Dynamic Editor Menu Whether you’re... Continue Reading

See the New Features and Enhancements in Minitab 18 Statistical Software

Eston Martz 7 June, 2017

It's a very exciting time at Minitab's offices around the world because we've just announced the availability of Minitab® 18 Statistical Software. Data is everywhere today, but to use it to make sound, strategic business decisions, you need to have tools that turn that data into knowledge and insights. We've designed Minitab 18 to do exactly that. We've incorporated a lot of new features, made some... Continue Reading

5 Conditions that Could Put Your Quality Program on the Chopping Block

Eston Martz 24 May, 2017

By some estimates, up to 70 percent of quality initiatives fail. Why do so many improvement programs, which are championed and staffed by smart, dedicated people, ultimately end up on the chopping block? According to the Juran Institute, which specializes in training, certification, and consulting on quality management, the No. 1 reason quality improvement initiatives fail is a lack of management... Continue Reading

Reducing the Phone Bill with Statistical Analysis

Eston Martz 10 May, 2017

One of the most memorable presentations at the inaugural Minitab Insights conference reminded me that data analysis and quality improvement methods aren't only useful in our work and businesses: they can make our home life better, too. The presenter, a continuous improvement training program manager at an aviation company in the midwestern United States, told attendees how he used Minitab... Continue Reading

How Can a Similar P-Value Mean Different Things?

Eston Martz 5 May, 2017

One highlight of writing for and editing the Minitab Blog is the opportunity to read your responses and answer your questions. Sometimes, to my chagrin, you point out that we've made a mistake. However, I'm particularly grateful for those comments, because it permits us to correct inadvertent errors. I feared I had an opportunity to fix just such an error when I saw this comment appear on one of... Continue Reading

Understanding Qualitative, Quantitative, Attribute, Discrete, and Continuous Data Types

Eston Martz 28 April, 2017

"Data! Data! Data! I can't make bricks without clay." — Sherlock Holmes, in Arthur Conan Doyle's The Adventure of the Copper Beeches Whether you're the world's greatest detective trying to crack a case or a person trying to solve a problem at work, you're going to need information. Facts. Data, as Sherlock Holmes says. But not all data is created equal, especially if you plan to analyze as part of... Continue Reading

Making the World a Little Brighter with Monte Carlo Simulation

Eston Martz 26 April, 2017

If you have a process that isn’t meeting specifications, using the Monte Carlo simulation and optimization tool in Companion by Minitab can help. Here’s how you, as a chemical technician for a paper products company, could use Companion to optimize a chemical process and ensure it consistently delivers a paper product that meets brightness standards. The brightness of Perfect Papyrus Company’s new... Continue Reading

Do Executives See the Impact of Quality Projects?

Eston Martz 19 April, 2017

Do your executives see how your quality initiatives affect the bottom line? Perhaps they would more often if they had accessible insights on the performance, and ultimately the overall impact, of improvement projects. For example, 60% of the organizations surveyed by the American Society for Quality in their 2016 Global State of Quality study say they don’t know or don’t measure the financial... Continue Reading

Why Is Continuous Data "Better" than Categorical or Discrete Data?

Eston Martz 7 April, 2017

Earlier, I wrote about the different types of data statisticians typically encounter. In this post, we're going to look at why, when given a choice in the matter, we prefer to analyze continuous data rather than categorical/attribute or discrete data. As a reminder, when we assign something to a group or give it a name, we have created attribute or categorical data. If we count something, like... Continue Reading

Eston Martz