Statistics Article

Larry Silverberg’s picture

By: Larry Silverberg

Some 20 years ago, my colleague Chau Tran and I developed a way to simulate the trajectories of millions of basketballs on the computer.

We went to the coaches and assistant coaches at North Carolina State University, where we are based, and told them we had this uncommon ability to study basketball shots very carefully.

Mike Richman’s picture

By: Mike Richman

Sustainable performance improvement is simply impossible without a firm handle on the precepts and tools of statistical process control (SPC). It is for this reason that we cover industrial statistics so frequently here at Quality Digest. After all, as the great Scottish physicist and engineer Lord Kelvin once said, “If you cannot measure something, you cannot improve it.”

Bonnie Stone’s picture

By: Bonnie Stone

Lean, also known as “lean manufacturing” or “lean production,” focuses on maximizing customer value by removing waste and eliminating defects. Lean tools are about understanding the process, looking for waste, preventing mistakes, and documenting what you did. 

Multiple Authors
By: Scott A. Hindle, Donald J. Wheeler

In theory, a production process is always predictable. In practice, however, predictable operation is an achievement that has to be sustained, which is easier said than done. Predictable operation means that the process is doing the best that it can currently do—that it is operating with maximum consistency. Maintaining this level of process performance over the long haul can be a challenge. Effective ways of meeting this challenge are discussed below.

John Flaig’s picture

By: John Flaig

Story update 9/26/2017: The words "distribution of" were inadvertently left out of the last sentence of the second paragraph.

Some practitioners think that if data from a process have a “bell-shaped” histogram, then the system is experiencing only common cause variation (i.e., random variation). This is incorrect and reflects a fundamental misunderstanding about the relationship between distribution shape and the variation in a system. However, even knowledgeable people sometime make this mistake.

Ville Satopaa’s picture

By: Ville Satopaa

At a 1906 livestock show in Plymouth, England, nearly 800 people participated in a contest to guess the weight of a slaughtered ox. The average of these estimates was 1,197 pounds. This is remarkable because the true weight of the ox turned out to be 1,198 pounds. The average was only one pound away from the truth. How could it be so accurate? Perhaps by chance?

Barbara A. Cleary’s picture

By: Barbara A. Cleary

If you get off the highway and take an alternate route when traffic slows to one lane, you are making a prediction. Likewise, if you decide to invite someone to dinner, that too is a prediction. The scientific method? Predictive in nature. Every time you make a decision, you are making a prediction of an outcome, and choosing one over another based on this prediction.

Dirk Dusharme @ Quality Digest’s picture

By: Dirk Dusharme @ Quality Digest


Our August 11, 2017, episode of QDL looked at the role of technology in after-market service, stairs that help you up, Fidget Cubes, and more.

“Climbing Stairs Just Got Easier With Energy-Recycling Steps”

These stairs actually help you go up.

Multiple Authors
By: Phil Klotzbach, Michael M. Bell

June 1 marked the official start of the Atlantic hurricane season, which runs through the end of November. It’s a busy time for us at the Tropical Meteorology Project in Colorado State University’s (CSU) Department of Atmospheric Science, where we are issuing our 34th annual Atlantic basin seasonal hurricane forecast.

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