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. […] read more

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 […] read more

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 […] read more

On March 17th, 2018, posted in: Project Management by

Rational Subgrouping of Data for Control Charts

Control charts are a tool to evaluate the performance of a process over time.   Think of the process as a river that is flowing past the point where we will collect data.  We must decide what to measure, how to measure, where to measure and how often to collect data from the process.   The story […] read more

On March 6th, 2018, posted in: Articles, Six Sigma by Tags: ,