Author Archives: developers

Statistical Significance and Practical Significance

When we work on process improvement, we need to check our results to see if the output of the process was changed for the better.  There are two ways to evaluate the results, practical significance and statistical significance.  We need to verify that the results are significant in both respects.  At the risk of stating […]

Common Misconceptions about Six Sigma

Our online Green Belt program includes an assignment where students are introduced to Six Sigma by reading a lecture, reading Chapter One in the text, and viewing several videos.  They are then challenged to explain how the readings and videos either reinforced or changed their preconceived notion of what Six Sigma is, based on what […]

Are we solving the right problem?

Students in our Green Belt course analyze and comment on a case study that deals with products that are returned by customers.  They are challenged to discuss what was done well in the case and what could have been done better. The products being returned for credit are data storage systems that are suspected of […]

Don’t like the data? Throw it out!

One of the first tasks our Black Belt students are asked to do when completing a project is collect data over time and create control charts for the primary output metric.  The purpose of these control charts is to establish baseline performance, and to determine if the process is stable. One of my students is […]

Economic Impact and Project Selection

Our Six Sigma Green Belt course includes a lesson on project selection.  Students are tasked to identify three or more potential improvement projects and make estimates of the cost to plan and execute the projects in dollars as well as the economic impact of completing the projects in dollars.   They then must explain which project […]

How Accurate and Reliable is Your Data?

Six Sigma is a process improvement methodology that uses facts and data to make decisions, not hunches and opinions.  It is obviously important that we use facts and data that are accurate and reliable.  The more important the decision and the more serious the consequences, the more care we need to take when collecting data. […]

Which Index is Representative of How the Stock Market is Really Performing?

In an earlier article in this series I discussed the use of sample data drawn from a larger population for the purposes of making decisions.  The data in the sample must be representative of the larger population in order for it to be useful in decision making.  Consider the stock market in general.   What is […]

To Transform Data, or Not to Transform, That is the Question!

In a previous article in this series I discussed whether or not to transform data that is non-normally distributed in order to make the data normally distributed.  In that article I stated the following: “Data that follow a distribution that is either not symmetric or that is symmetric but not bell shaped are said to […]