Archive for the ‘Six Sigma Tools’ Category

Where Do Those Six Sigma Statistics Come From?

Friday, January 13th, 2012

A student of mine had numerous questions about the various statistics used in Six Sigma. Here is my response to him in an open email:

The questions you are asking regarding “Where do these statistics come from?” require entire courses in statistics to answer. In Lean Six Sigma we take information from a dozen or so statistics courses, project management courses, psychology courses, business courses, mathematics courses, etc. and put it into an action framework that can be used to make fast improvements. We probably present less than 10% of the information you would receive if you sat through all of these courses, but we do so in less than 5% of the time it would take to complete all of these courses. It’s a tradeoff. We make the greatest compromises in the field of statistics. We discuss the use and interpretation of a select subset of statistics, and answer the question “where do these statistics come from?” by saying “they come from computer software.” While most are satisfied with this answer, some find the answer to be most unsatisfying. Judging from your questions, I suspect you are in the latter group.

anova-table-calculations-e-handbook-of-statistics

Two-Way ANOVA Calculations from E-Handbook of Statistics

Assuming you don’t have the time or the desire to take all of the courses relating to the Lean Six Sigma body of knowledge, but still seek answers to the specific statistics you asked about, I recommend the E-Handbook of Statistical Methods. This reference source is free and very comprehensive. It’s easy to search and will give you the answers you seek. For example, I searched on the term sum of squares, which you asked about, and the search returned pages on the half-normal probability plot (your question about fig. 10.26,) 1-way ANOVA (several of your question were about these calculations,) and several other related topics. A search on ss interaction provides answers to your question about the calculation of this intermediate statistic.

Sorry I can’t address all of your questions via email, but perhaps the reference above will start you on your way to answers. I had the same questions when I started learning about quality improvement nearly 45 years ago, and I am still looking for answers to questions today. Have fun!

Tom Pyzdek

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Statistical Surprises and Absurdities

Sunday, December 18th, 2011

I held a Webinar for Pyzdek Institute students entitled Statistical Surprises and Absurdities. Topics discussed included sampling bias, misused and misleading averages, distorting results by use of selective data weighting, selective reporting, missing information, distorted graphics, Say What? and So What? statistics, and much more! Here’s the recording

Here’s a link to the slides presented in the webinar.

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Free Webinar about a New Control Chart

Thursday, September 22nd, 2011

The Laney p’ Control Chart is an exciting innovation in statistical process control (SPC). The classic control charts for attributes data (p-charts, u-charts, etc.) are based on assumptions about the underlying distribution of their data (binomial or Poisson). Inherent in those assumptions is the further assumption that the “parameter” (mean) of the distribution is constant over time. In real applications, this is not always true (some days it rains and some days it does not). This is especially noticeable when the subgroup sizes are very large. Until now, the solution has been to treat the observations as variables in an individual’s chart. Unfortunately, this produces flat control limits even if the subgroup sizes vary. David B. Laney developed an innovative approach to this situation which has come to be known as the Laney p’ chart (p-prime chart.) It is a universal technique that is applicable whether the parameter is stable or not.

About Your Presenter, David B. Laney

David B. Laney

David B. Laney

David B. Laney worked for 33 years at BellSouth as Directory of Statistical Methodology. He is a pioneer at BellSouth in TQM, DOE, and Six Sigma. David’s p-prime chart is an innovation that is being used in a wide variety of areas. It is now included in many statistical applications, such as Minitab and SigmaXL. David is enjoying retirement with his family in the Birmingham, Alabama area.

Date: Wednesday, September 28, 2011

Session #1, 1:00 PM Eastern Time. Click here to register.
Session #2, 7:00 PM Eastern Time. Click here to register.

 

Update

Click here to view a video recording of David’s webinar.

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Free E-handbook of Statistical Methods

Thursday, September 8th, 2011

Click here to access the NIST/SEMATECH e-Handbook of Statistical Methods. NIST is an agency of the US Department of commerce, so this work was undertaken at public expense. It covers literally every statistical tool used in Lean Six Sigma, and many, many more. It includes hundreds of case studies and examples. Best of all, it’s free! Enjoy!

nist-ehandbook-example

Skewness from NIST E-handbook

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Tom Pyzdek’s Public Folder

Tuesday, September 6th, 2011

Click the folder icon below to go to my public folder where I share files of interest to improvement and innovation professionals.

When you visit the folder you may also wish to add the RSS feed to Outlook or your feed reader to stay up to date.

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JMP Offers Free Webcasts

Thursday, September 1st, 2011

Mastering JMP® Webcasts

Sept. — Nov. 2011 • Registration required
Each week JMP technical experts will delve into topics to help you master the extensive analysis and data visualization capabilities of JMP statistical discovery software.
Webcasts featuring a variety of topics will be held most Thursdays from 2 to 3 p.m. ET. Each session includes demos, examples, tips and tricks to help you become proficient in the topic of the day. Participants can submit questions to be answered during the session.
View the schedule and register.

Webcast Schedule

  • Finding the Best  Predictive Model for Your Data, Sept. 29
  • Understanding the Impact of Measurement Variability on Quality, Oct. 6
  • Predictive Modeling  for  High Dimensional Data, Oct. 13
  • Using Stagewise Experimentation to Find Best Process Conditions, Oct. 20
  • Building Forecasting Models, Oct.27
  • Uncovering the Structure of Your Data, Nov. 3
  • Analyzing Sensory Data to Develop Consumer Products, Nov. 10
  • Building Custom Maps That Help Visualize Your Analyses, Nov. 17

Can’t make it to a live webcast? On-demand webcasts are available. View the list of topics.

 


PLEASE JOIN US FOR A COMPLIMENTARY WEBCAST
Mastering JMP® Webcasts
Sept. — Nov. 2011 • Registration required

Each week our technical experts will delve into topics to help you master the extensive analysis and data visualization capabilities of JMP statistical discovery software.

Webcasts featuring a variety of topics will be held most Thursdays from 2 to 3 p.m. ET. Each session includes demos, examples, tips and tricks to help you become proficient in the topic of the day. Participants can submit questions to be answered during the session.

View the schedule and register.

Webcast Schedule

  • Finding the Best  Predictive Model for Your Data, Sept. 29
  • Understanding the Impact of Measurement Variability on Quality, Oct. 6
  • Predictive Modeling  for  High Dimensional Data, Oct. 13
  • Using Stagewise Experimentation to Find Best Process Conditions, Oct. 20
  • Building Forecasting Models, Oct.27
  • Uncovering the Structure of Your Data, Nov. 3
  • Analyzing Sensory Data to Develop Consumer Products, Nov. 10
  • Building Custom Maps That Help Visualize Your Analyses, Nov. 17

Can’t make it to a live webcast? On-demand webcasts are available. View the list of topics.


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Swiss Army Knife Control Chart Webinar Materials Now Available

Wednesday, July 27th, 2011

The slides presented in this webinar are now available, click here.

To view a recording of this webinar, click here.
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Minitab offers free Quality Companion webinar

Tuesday, May 10th, 2011

State College, PA (PRWEB) May 04, 2011

Minitab, the leading provider of software for quality improvement, is offering a free webinar to highlight how its process improvement software can support Lean Six Sigma projects. ”Meet Quality Companion” will be held on May 19, 2011, at 11:00 a.m. EDT (GMT-4:00). Registration is free at www.minitab.com/training/web-events/ Space is limited.

Starting in 2011 The Pyzdek Institute provides all of its online training students with 1-year licenses for Quality Companion, as well as Minitab. Quality Companion provides a large number of useful tools to help practitioners with their projects. These include a number of tools that are designed to help organize and track individual projects as they move through the DMAIC process, as well as tools to help design reports and presentations. It is possible to create customize Quality Companion templates for other types of projects, as well as for other purposes. For example, Pyzdek Institute students are provided with Quality Companion templates designed to reflect the training modules included in their particular training class.

In addition, Quality Companion integrates the various parts of the project. For example, variables identified as possible causes on a fishbone diagram are automatically shown when performing other analyses.

Besides being useful for managing individual projects, Minitab provides a free dashboard product that allows managers, Master Black Belts, and Black and Green Belts to keep track of portfolios of Quality Companion projects.

The complete webinar announcement, which includes a video overview of Quality Companion, is available here.

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Using QI Macros to Test Normality

Tuesday, April 19th, 2011
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Statistical Engineering

Monday, April 11th, 2011

In the movie “The Graduate,” the new graduate is told by a would-be mentor to remember only one word as he heads out into the world: Plastics. Times have changed. Hal Varian, the chief economist at Google says, ‘‘I keep saying that the sexy job in the next 10 years will be statisticians. And I’m not kidding.’’ Statistical methods are being used by a larger cross-section of people in a wider variety of industries than ever before. There are numerous reasons for this. Nearly everyone has what was once considered to be a supercomputer sitting on their desktop. Powerful statistical software is widely available, including popular packages like Minitab, JMP, SAS and SPSS, and extremely powerful free software. Oracle’s Crystal Ball software makes it possible to create a statistical distribution for any cell in a spreadsheet, making statistical simulation a snap. While becoming more sophisticated, the software is also becoming easier to use. Output is increasingly graphical and easier to explain to laypersons. The number of people trained in Lean Six Sigma methods is growing rapidly. There is an enormous amount of data saved in public and corporate data warehouses. The list goes on and on.

But perhaps the most important reason for the ballooning use of statistics is: it works.

If we take Aristotle’s logic as the historical starting point for rational analysis, and Galileo’s experimental method as the next major leap, then statistical methods might be viewed as the next step in applied analysis. Many problems don’t lend themselves to solution by pure logic nor by carefully planned and controlled experimentation. Most organizations, especially in the commercial sector, must deal with so many problems and such a dynamic external environment that they are forced to make quick decisions despite large uncertainty, then move on to the next problem. Statistical methods help these decision makers evaluate the evidence and make better decisions quickly. The tools and technology described in the first paragraph make this easier than ever before.

This situation is much more akin to engineering than it is to pure science. The approach has been termed “Statistical Engineering.” Authors Roger W. Hoerl and Ron Snee describe Statistical Engineering as follows:

“The statistical engineering discipline [is] the study of how to utilize the principles and techniques of statistical science for benefit of humankind. From an operational perspective we define statistical engineering as the study of how to best utilize statistical concepts, methods, and tools and integrate them with information technology and other relevant sciences to generate improved results. In other words, engineers—statistical or otherwise—do not focus on advancement of the fundamental laws of science but rather how they might be best utilized for practical benefit.

This definition goes beyond applied statistics. Statistical Engineering implies the application of statistics in a systematic framework that utilizes technology to create or improve products, processes and services that improve the lives of people. Disciplines such as Lean Six Sigma, Quality Engineering, Reliability Engineering, and others can be said to do this to some degree, but there are other ways to use Statistical Engineering, some quite unexpected. Billy Beane, general manager of MLB’s Oakland A’s and protagonist of Michael Lewis’s book Moneyball, had a problem: how to win in the Major Leagues with a budget that’s smaller than that of nearly every other team. Conventional wisdom long held that big name, highly athletic hitters and young pitchers with rocket arms were the ticket to success. But Beane and his staff, buoyed by massive amounts of carefully interpreted statistical data, believed that wins could be had by more affordable methods such as hitters with high on-base percentage and pitchers who get lots of ground outs. Given this information and a tight budget, Beane defied tradition and his own scouting department to build winning teams of young affordable players and inexpensive castoff veterans. Author Michael Lewis examines how in 2002 the Oakland Athletics achieved a spectacular winning record while having the smallest player payroll of any major league baseball team. Given the heavily publicized salaries of players for teams like the Boston Red Sox or New York Yankees, baseball insiders and fans assume that the biggest talents deserve and get the biggest salaries. However, argues author Michael Lewis, little-known numbers and statistics matter more.

Statistical Engineering is not limited to applied statistics, theoretical statistics have a place too. In a paper published in the April-June 2011 issue of the journal Quality Engineering author Philip R. Scinto offers this list of Statistical Engineering attributes:

  • Meets high-level needs of an organization
  • Work/study for the greater good
  • Use of statistical concepts and tools
  • Collaborative effort with other sciences
  • Integrated with other sciences
  • Documented protocol
  • Activity continuous with sustainable life
  • Improved results

It isn’t necessary that all items on the list be checked off, but the list is useful in evaluating whether an activity qualifies as Statistical Engineering or if it’s merely another clever use of statistics. The important thing isn’t the label we apply, but the improvement that can be achieved by properly using statistical methods along with science and technology to achieve a challenging goal.

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