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Process Capability

Blog posts and articles about tools for assessing the capability of a process in manufacturing and service situations.

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
by Matthew Barsalou, guest blogger Process capability analysis using Minitab Statistical Software’s Capability SixpackTM can be taught using a catapult. A process capability analysis is performed to determine if a process is statistically capable. In my last blog post, I collected data from a first run of catapult results and found that the run not only had a large amount of variability, it also... Continue Reading
by Matthew Barsalou, guest blogger We can use a simple catapult to teach process capability analysis using Minitab Statistical Software’s Capability SixpackTM. Here's how. A process capability analysis is performed to determine if a process is statistically capable. Based on the results of the capability study, we can estimate the amount of defective components the process would produce. However, a pr... Continue Reading
Here at the lightsaber factory, we've completed several steps in doing a capability analysis: We made sure our data was collected and entered correctly in Minitab We identified the distribution of the data We made sure all of our assumptions checked out We’re getting close to our deadline, and it’s finally time to carry out our Capability Analysis and see if we are manufacturing our lightsabers to... Continue Reading
I had the privilege of talking with Sue Schlegel, Lean Six Sigma black belt and quality improvement mentor at White Sands Missile Range, which is located just outside of Las Cruces, New Mexico. Schlegel and an improvement team at White Sands recently conducted a Lean Six Sigma project to streamline surveillance processes and they used Minitab to analyze the data. We found Sue’s story... Continue Reading
In my last post, we talked about using statistical tools to identify the right distribution of our lightsaber manufacturing data. Now that we have our data in Minitab along with a specific distribution picked out, we can find out if we are dealing with an in-control process. If the process is not in control, the capability estimates will be incorrect. Thus, an extremely important (and often... Continue Reading
Have you ever been a victim of a statistical misconception that’s affected how you’ve interpreted your analysis? Like any field of study, statistics has some common misconceptions that can trip up even experienced statisticians. Here are a few common misconceptions to watch out for as you complete your analyses and interpret the results. Mistake #1: Misinterpreting Overlapping Confidence Intervals Wh... Continue Reading
Want to learn more about analyzing data? Try taking a page from Aesop's book.  Well...really, I'm suggesting taking multiple pages from Minitab's book, but my suggestion stems from an idea that Aesop epitomizes.   Aesop was no fool. When he wanted to convey even the heaviest of lessons, he didn't waste time detailing the intellectual and philosophical arguments behind them. He didn't argue, cajole,... Continue Reading
New to confidence intervals?  Here are some important things to keep in mind! Confidence Intervals: are used to estimate population parameters (commonly the process mean, standard deviation, % of defective units, or even capability indices).  provide more meaningful information than any random sample statistic for characterizing the population. MINI-TIP:See “Tip 1: Every sample statistic is a little... Continue Reading
In my previous post, you learned how to prepare your data for capability analysis in Minitab. Now let's see where we need to go in the statistical software to run the correct Capability Analysis. When it comes to capability analysis, Minitab offers a few different choices. We offer Normal Capability Analysis for when your data follow a normal distribution. If your data follow a different... Continue Reading
In the past couple of years, I've noticed a new acronym popping up across the Web. In case you've not yet encountered it, "FML" typically appears in social media updates about something gone awry.  As in, "The cat ate my homework. FML!"  Or, "My production line just broke down, and now the company is going to be short on a major order. FML!"  This acronym reminds me of an abbreviation used in... Continue Reading
It's your first day at the Jedi Temple, working as a lightsaber manufacturer. Your first task on the job is to run a Capability Analysis on the length of lightsabers being produced. Your main concern is to see if the lightsabers fit within the required length specifications set forth by the Jedi Council. You aren’t quite sure where to start. Thankfully, Minitab Statistical Softwareis there to help... Continue Reading
It's no secret that in the world of control charts, I- and Xbar- are pretty much the popular kids in school.  But have you ever met their cousin EWMA? That's him in the middle of the class, wearing the clothes that look nice but aren't very flashy. You know, when Xbar- and I- were leading the championship football team last month, EWMA won the state tennis championship?  I didn't go either --... Continue Reading
The Minitab Fan section of the Minitab blog is your chance to share with our readers! We always love to hear how you are using Minitab products for quality improvement projects, Lean Six Sigma initiatives, research and data analysis, and more. If our software has helped you, please share your Minitab story, too! Throughout my 15 years as a Six Sigma Initiative Leader, Consultant, Trainer, Black... Continue Reading
In my last post, I discussed how quality professional Bill Howell chose to manage his diabetes diagnosis by treating it as a Six Sigma project. Since a key metric in controlling his disease was keeping his blood glucose levels below 125 mg/dL, he tested his blood using a meter three times per day and then charted his data to see how his levels changed over time. He ensured his measurement systems... 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
I recently had the chance to talk to Brett Warland, global director of process improvement at PolyOne Corporation. The word “global” is often present in the titles of many organization’s process improvement programs and employee job titles that deal with quality. This can convey not only an international emphasis on process improvement at worldwide branches of the company, but also that CI methods... Continue Reading
The Minitab Fan section of the Minitab blog is your chance to share with our readers! We always love to hear how you are using Minitab products for quality improvement projects, Lean Six Sigma initiatives, research and data analysis, and more. Today we learn how an avid gamer used design of experiments to boost his performance in his favorite driving game. If our software has helped you, please sha... Continue Reading
Sheriff Taylor: What’s wrong Barney?Barney: Someone spilled alphabet soup all over my capability output! Wait till I catch the practical joker who did this!! They’ll be sorry!!Sheriff Taylor: That’s not alphabet soup, Barney. Those are capability indices.Barney: I don’t see any indecisives, Andy. I just see a big mess of letters: Cp, Pp, Cpk, Ppk, Cpm, PPM…LMAO!Sheriff Taylor: LMAO is not part of... Continue Reading
Back when I used to work in Minitab Tech Support, customers often asked me, “What’s the difference between Cpk and Ppk?” It’s a good question, especially since many practitioners default to using Cpk while overlooking Ppk altogether. It’s like the '80s pop duo Wham!, where Cpk is George Michael and Ppk is that other guy. Poofy hairdos styled with mousse, shoulder pads, and leg warmers aside, let’s... Continue Reading