# Tips and Techniques for Statistics and Quality Improvement

Blog posts and articles about using Minitab software in quality improvement projects, research, and more.

A 2 proportion test helps you determine whether two population proportions are significantly different -- such as whether the proportion of men who support a candidate is different from the proportion of women who support the same candidate. It uses the null hypothesis that the difference between two population proportions equals some hypothesized value (H0: p1 - p2 = P0), and tests it against an... Continue Reading
Everyone loves the soft feel of a cotton t-shirt! Unfortunately, the very properties that make cotton fabric so soft also make it prone to wrinkling and tearing. Researchers from the National Textile University in Faisalabad, Pakistan embarked on a study to predict the best fabric properties for strong, crease-free cotton—and they used Minitab to help. Cloth manufacturing plants strive to create a... Continue Reading
We humans do have a tendency to succumb to gold rush fever. And this can happen even in the left-brained, rational field of statistics. After we collect our data, it’s difficult to resist the urge to desperately dash for p-values, as if they were 70% off at Macy’s the day after Thanksgiving.But no matter how well-versed you are in statistics, it’s good practice to get into the habit of intuitively... Continue Reading
In an earlier post, I focused on using Minitab to present the coupon data I collected from my e-mail inbox into a bar chart. The bar chart made it easy for me to visually analyze which days of the week are better or worse for receiving the best coupons from my favorite retailers. As a reminder, here’s how I ranked each coupon’s worthiness: Not worth your timeOffering average savings (A “noteworthy”... Continue Reading
Time series plots help us see variations over time by displaying observations on the y-axis against equally spaced time intervals on the x-axis. In Lean Six Sigma, they can show you the before-and-after effects of a process change. I recently used a time series plot to see how the price of gold has changed over time. After reaching record highs recently, gold prices have dipped, although some... Continue Reading
It’s summer and maybe you’re traveling to Florida’s coast for a beach vacation (or just wishing you were, like I am)! I got the chance to talk to Dr. Henry Briceño from the Southeast Environmental Research Center (SERC) about how he and his team use statistics to monitor Florida’s water quality. The center’s research projects throughout South Florida have provided a basis for management decisions... Continue Reading
Ever feel frustrated with the flip-floppy results reported in the medical news? Today a cup of coffee will lead you to an early grave. Tomorrow it will ensure that you’ll be dancing a jig on your 99th birthday. Every day, it seems there’s a new study that contradicts a previous finding.   In response, some people throw up their hands in helplessness. Others shrug—then chug another double-shot of... Continue Reading
Statistics can be confusing, especially when you look under the hood at the mathematical engines that underlie it. That's why we use statistical software to do so much of the work for us, and why we use tools like p-values to help us make sense of what our data are saying.The p-value is used in basic statistics, linear models, reliability, multivariate analysis, and many other methods. It's a ... Continue Reading
Whether we're talking about sports or the best way to improve a process through Lean Six Sigma, it's good practice to verify things you "know" with some data. Quick and easy data analysis sometimes reveals that what everyone took as common knowledge just isn't true. On the other hand, looking at data also can confirm your suspicions.For example, it's no secret that LeBron James didn't play well... Continue Reading
I was 'lucky' enough to learn about how Betfair, one of the world's largest online sports betting communities, employs quality improvement in their day-to-day business. Here's a snippet of the case study: Betfair turned to Minitab when a crucial process for helping new customers get started needed improvement. The company invests heavily in different marketing activities, including an outbound... Continue Reading
We recently published a few new case studies featuring the Northern Sydney Central Coast Health Service (NSCCHS) and their commitment to quality improvement. The health service is based in Australia and extends from the Sydney Harbor to the northern reaches of the Central Coast, including a total of 11 different facilities. After the NSCCHS realized the success of a few isolated improvement... Continue Reading
I’m an avid shopper and coupon-clipper. I receive most of my coupons via e-mail and I often wonder what day of the week the best coupons will be e-mailed. In my attempt to live a Lean life, I think finding this out will save me time and prevent me from opening some of the hundreds of promotional e-mails I get each week. Before performing any data analysis in Minitab, I decided to assign the... Continue Reading
As I mentioned before, accurate instruments won’t yield good data if you haven’t answered three fundamental questions that should precede every measurement system analysis. Whether you're doing a 6 Sigma project, or data analysis in support of a research project or some other goal, you need to be careful about how, when and where you gather the data. Here’s how I learned that lesson the hard way.I... Continue Reading
Sometimes, statistical terms can seem like they were zapped down from outer space by sadistic, mealy-mouthed aliens: R-squared adjusted, heteroeskadasticity, 3-parameter Weibull distribution. But not all statistics terminology should leave you feeling woozy and glassy-eyed. Some terms  actually make intuitive sense. Knowing those terms can help you get a handle on output that may seem fuzzy at... Continue Reading
No, I’m not talking about meat that contains less fat or really healthy food! I’m talking about the Lean Six Sigma Manufacturing Techniques at work in your favorite fast-food restaurants. I attended an in-house Lean training a few months back taught by Paul Sheehy, one of Minitab’s technical training specialists. Paul explained Lean fundamentals through examples—including just some of the ways... Continue Reading
“Fear leads to anger, anger leads to hate, hate leads to suffering.” Yoda This quotation sums up the way most people’s relationship to statistics develops. But not me. My name is Cody Steele, and I’m the guy who Eston Martz warned you about. From the time my 6-year-old self decided that Superman’s most amazing power was his intelligence, through buying a calculus book after college so that I could... Continue Reading
A recent study by Bank of America found that the proportion of Americans under 50 on Facebook is 96%. However, the second paragraph of the article questions the validity of the study. It says: A total of 418 participants were included in the polling. Such a limited sample size will surely bolster calls that the survey was statistically unreliable, but the persons questioned were supposed to... Continue Reading
Data collection involves taking measurements, and this seems like a simple thing when the subject is relatively simple.  However, even the simplest of cases has the potential to be messed up.  I found this out the hard way once. I hope sharing it helps you avoid a similar experience. Experienced researchers and quality practitioners know they need to verify that a measurement system provides valid... Continue Reading
When I was in middle school, I picked up the newspaper to read an article on the opponent our varsity football team was playing that night (for our younger audience, this is what a newspaper is). The article said the opposing team’s running back was averaging almost 6 yards per carry, which is very high. I decided that I wanted to keep stats during the game to see if he was able to average 6 yards... Continue Reading
"Gimme a latte grande with a double shot of statistical analysis. Hold the sugar."If I tried ordering that the next time I go to Starbucks, my barista would probably just give me a blank look. But the fact is that the world's best-known coffee company applies a great deal of statistical know-how to making sure customers get the best possible coffee, whether they're getting it at a Starbucks... Continue Reading