How Should the Sample Size be Selected for an X-bar Chart? (Part II)

An earlier article focused on the conceptual application of appropriate sample sizes for X-bar charts.  As we discussed, the purpose of control charts is to detect significant process changes when they occur.  When the proper sample size is selected, X-bar charts will...

How Should the Sample Size be Selected for an X-bar Chart? (Part I)

The purpose of control charts is to detect significant process changes when they occur. In general, charts that display averages of data/measurements (X-bar charts) are more useful than charts of individual data points or measurements. Charts of individuals are not...

How do I Choose the Appropriate Type of Control Chart

Proper control chart selection is critical to realizing the benefits of Statistical Process Control. Many factors should be considered when choosing a control chart for a given application. These include: The type of data being charted (continuous or attribute) The...

How do I Know What Product or Process Characteristics to Control?

While the construction of control charts is relatively straight-forward, often a more difficult question is “how do I know what process characteristic to control in the first place?” Clearly, controlling “everything” is not feasible or a smart use of limited...