Quality Improvement Statistics: Things I Learned While Writing Help

Hi, I’m Greg Fox, a writer in the Information Development department here at Minitab. Have you ever clicked “Help” in Minitab and been awestruck by the wealth of timely and truly helpful content suddenly revealed before your very eyes? I hope so, because I write that stuff. Well, me and several other very smart and dedicated folks. We work hard to provide you with the documentation that you need to get your job done and achieve success with Minitab Software.

Statistics is one of those things that doesn't always click right away. It's a different way of looking at the world and you learn a...

It Was the Best of Times, It Was the End of Times

I have been riding my bike to work lately instead of taking my car. I figured I could use the exercise. I figured it would be good for my health. I figured it might help stave off global warming. I figured wrong.  

I’ve noticed lately that the sky seems to get darker a little earlier every day. I asked my wife if she had noticed the same thing and she said, “When are going to take out that garbage like I asked?” I wasn’t sure I could tackle her garbage question, but I was reasonably confident that with the help of Minitab Statistical Software, I could get to the bottom of this darkness thing.

Tur...

"Mom, Dad Fed My Lunch Money to a Pokie!"

My son goes to the same high school as infamous Aussie rocker Angus Young, from AC/DC. If the school provided any of the inspiration for songs like “Highway to Hell” and “Dirty Deeds Done at a Discount”, I think my son will learn a lot there. In fact, he might even learn that gambling doesn’t pay.

On weekday mornings, I often walk my son to school and then hop a train into the city. As we’re approaching the school, we pass a club where they feature gambling. When we pass the club, I often say, “Hey, son. Wait here for a minute and I’ll go double your lunch money.” That always gets a big laugh....

Using Statistical Software to Skip Weekends and Holidays

The other day I was having lunch with a Minitab user. She asked if Minitab Statistical Software could calculate the number of business days between two dates, excluding weekends and holidays. “I’m not sure,” I said. “I’ll look into it."

I am happy to report that Minitab can indeed do this. Which is good, because this would be a pretty disappointing blog post otherwise. It’s actually really easy, you just use the NetWorkdays function in the Minitab calculator. It automatically excludes weekends, and if you list the holidays, it will exclude those as well. I’ll show you with an example.

In column...

Using G-Whiz Charts to Track Elusive Affirmations from Almost Adolescents

I have a 12-year-old son. This is not a unique condition. And you might think that I would be well prepared for the associated challenges, having been a 12-year-old son myself at one time. But you'd be wrong.

Regular readers of the blog might recall that my family and I recently moved from rural Central Pennsylvania to urban Sydney, Australia for 6 months. My son wasn’t too keen on the idea of leaving his friends and his dog behind to start 7th grade all over again in a new country. But his mother and I were confident that once we arrived, he would realize that we did, in fact, know what we...

Tally Hoe: Use Tally to Weed Out Those Pesky Typos in Data

The other day a colleague of mine mentioned a use for Minitab's Tally command that I didn't know about. I thought I would share it with you in the form of contrived anecdote. I hope you enjoy it.

Bob works at a manufacturing plant. You may remember Bob as the guy who was obsessed with gnomes. Well, his work with gnomes was so exemplary that he was promoted to work in the Garden Tool Division. Bob was sad to leave his gnomes behind, but the opportunity was too good to pass up, so Bob traded in his gnomes for rakes, shovels, and hoes.

When Bob got to the tool plant, he found that something was...

Quality Analysis and Outliers: This Time Samoa has Really Crossed the Line

I am an outlier. Of the people who work in my department, I go to the fewest meetings, I talk with others the least, and I make the least use of our exercise facilities. But this is not because I am negligent, anti-social, or lazy. It is because I am separated from the rest of my department by about 10,000 miles.

You see, my family and I have had the opportunity recently to move to beautiful Sydney, Australia. And at 3 PM on Friday in Pennsylvania, while my colleagues are discussing nonparametric statistics, SIPOC, and project charters, I'm plotting my route to the beach because it is 7 AM...

Gnome Power (and Sample Size)

I was playing around with the power and sample size graphs in Minitab recently, and I noticed something interesting. Power, for the uninitiated, is usually described as the likelihood that you will find a significant effect or difference when one truly exists. There is a lot of good content on Power in the Minitab Help, StatGuide and Glossary. In any case, rather than simply describe what I found, I thought I’d invent a completely contrived, obviously fabricated, and wildly unrealistic example to illustrate. You're welcome.

Meet Bob. Bob works for the company that leads the nation in...

So, Why Does the World Trust Minitab?

I was in the kitchenette this morning, diligently scrubbing dried food bits off of my extensive collection of dirty forks, when a recent hire walked in.

“How are you doing?” I asked.

“Super!” he said, and he genuinely seemed to mean it. And then he spilled hot coffee on his hand, and his attitude changed a little. But only briefly.

When you ask folks here at Minitab how they are doing, you frequently do get answers like "Super," "Never better," and "Great." Sure, some of them are lying, but the truth is that Minitab really is a great place to work. (Don't take my word for it; it’s documented.)...

Control Charts and a Visit With My Doctor - Part 2: It’s Important to Talk to Your Doctor About Overdispersion

I followed the nurse down the long beige hallway and had a seat. “The doctor will be with you shortly,” she said as she turned to leave.

It had been a month since my last visit. My doctor had prescribed me a statin drug to lower my cholesterol. I had prescribed him a P chart to monitor his wait times. I was anxious to find out how both had worked.

“Ah there he is,” said my doctor as he entered the room and began his obligatory hand sanitization ritual. “Well, I’ve got some good news and some bad news.”

“Let’s start with the good news,” I said.

“Certainly. Well your labs are back and your...

Control Charts and a Visit With My Doctor - Part 1: Monitoring Cholesterol, and Wait Times

So I’m in my doctor’s office the other day and he tells me my “LDL” is “out-of-control.”

“What’s an LDL?” I asked.

“I’m glad you asked,” he said. “You see, LDL is the bad cholesterol and you want it to be low.”

“So there’s a good cholesterol?” I asked.

“Yes, it’s called HDL, and yours should be higher.”

“Oh, so the HDL should be higher than the LDL? Kind of like how the UCL is higher than the LCL on a control chart?”

“Not exactly,” he said. “LDL is usually higher than HDL, but your LDL is too high. I’m going to try you on a statin drug.”

“Will that bring my cholesterol under control?” I asked.

“...

Disaster Recovery for Control Charts

So I’m standing at my desk last Tuesday, when my legs suddenly turn to Jell-O. Then I notice the overhead lights gently waving. Soon folks are popping out of their offices with quizzical, sometimes queasy expressions. A few phone calls and Internet searches confirm that we have just experienced a very rare, East Coast earthquake. One centered in Virginia but felt from Georgia to Maine. Wow.

We were all a bit distracted for a while. Even the smallest bounce in the floor from someone walking by had us thinking about aftershocks. Toward the end of the day, I found myself at my window, gazing out...