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Label your charts!
Charts you share with others need a bodyguard of text to be self-explanatory, avert misunderstandings, and support learning. None of this matters when you chart exclusively for your own use, but it...
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Update on Data Science versus Statistics
Based on the usage of the terms in the literature, I have concluded that statistics has been subsumed under data science. I view statistics as beginning with a dataset and ending with conclusions,...
View ArticleUsing Regression to Improve Quality | Part III — Validating Models
Whether your goal is to identify substitute characteristics or solve a process problem, regression algorithms can produce coefficients for almost any data. However, it doesn’t mean the resulting models...
View ArticleUsing Regression to Improve Quality | Part II – Fitting Models
This is a personal guided tour of regression techniques intended for manufacturing professionals involved with quality. Starting from “historical monuments” like simple linear regression and multiple...
View ArticleUsing Regression to Improve Quality | Part I – What for?
In quality, regression serves to identify substitutes for true characteristics that are hard to observe and to find the root causes of technically challenging process problems. It is a major topic in...
View ArticleRankings and Bump Charts
Hectar’s Audrey Bourolleau and Francis Nappez presented their findings about greenhouse gas emissions in the industrial production of bread baguettes at the 2024 Lean Summit in France. They see a major...
View ArticleWhen Not to Connect the Dots
When plotting a sequence of points, should we connect the dots into a line? We usually do, but it shouldn’t be a foregone conclusion. Every chart element should have a clear and precise meaning: if we...
View ArticleProcess Control and Gaussians
The statistical quality profession has a love/hate relationship with the Gaussian distribution. In SPC, it treats it like an embarrassing spouse. It uses the Gaussian distribution as the basis for all...
View ArticleMeasurement Errors
Like spouses in murders, errors are always the prime suspect when measurements go awry. As soon Apollo 13 had a problem, a Mission Control engineer exclaimed, “It’s got to be the instrumentation!” It...
View ArticleProcess Capability Indices
Within the quality profession, a capable process is one with a high . In the field, it is not quite so simple. My colleague Joerg Muenzing recently shared concerns about the process capability indices:...
View ArticleOrbit Charts, Revisited
Data visualization is not just the art of presenting data to an audience. Upstream from this, you use visualizations in data cleaning to identify defective points, and in exploratory analysis, to...
View ArticleEffect of COVID-19 Vaccines on Excess Deaths
Even on LinkedIn, you still see posts and comments asserting that the COVID-19 vaccines aren’t “real” and alleging that they do more harm than good. This is usually based on articles of questionable...
View ArticleAnalyzing Variation with Histograms, KDE, and the Bootstrap
We review techniques from histograms to Kernel Density Estimators (KDE) to analyze the variability of measurements through the example of water quality data from India in 2021. The post Analyzing...
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Always the Hurricanes Blowing (Part 2)
This post and the previous one use Atlantic hurricanes as a vehicle to show what various visualizations can do. It’s not about second-guessing the data scientists at NOAA who have produced similar...
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Sales Forecasts – Part 3. Generating Probability Forecasts
My last two long posts were about evaluating sales forecasts. They begged the question of how you generate these forecasts. This is a partial answer, about what you can tell from a history of sales...
View ArticleCOVID-19 Pfizer Vaccine Study On Teens
Pfizer-BioNTech just announced the results of a COVID-19 vaccine clinical trial of 12- to 15-year olds. Because the vaccinated group had 0 infections, the news media jumped to the conclusion that the...
View ArticleMore about Toyota and SPC
The post on Does Toyota Use SPC? elicited many comments on LinkedIn. Some suggested that it was scoping SPC too narrowly when contrasting it with Toyota’s approach. In fact, SPC as referenced in the...
View ArticleDoes Toyota Use SPC?
As part of a discussion started by Lance Richardson on LinkedIn, I stated as a fact that SPC was not part of the Toyota Production System (TPS), which prompted several contradictors to tell me I didn’t...
View ArticleSeries Of Events In Manufacturing
Factories are controlled environments, designed to put out consistent products in volumes according to a plan. Controls, however, are never perfect, and managers respond to series of events of both...
View ArticleThe Math of COVID-19, And Factories
Whether we like it or not, the past months have given us a crash course in epidemiology. COVID-19 has taken terms like reproduction number, herd immunity, social distancing, or flattening the curve...
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