Control Charts for Variables (A8503)

Learn how to interpret variable control charts in order to determine whether or not a process is in statistical control.

Prerequisites

This lesson is designed for participants familiar with the principles of statistical process control, the basic components of control charts, and the characteristics of a normal curve. A knowledge of basic mathematical skills is recommended.

Description

This lesson explains how to interpret variable control charts in order to determine whether or not a process is in statistical control. The lesson introduces the concept of performance-based limits for process control and presents basic guidelines for proper sampling. In addition, the principles for interpreting control charts are presented.

Objectives

Identify variables. Explain how the control limits for a process are related to a normal curve. Explain how the central line may be identified for mean, median, and range charts. Identify the criteria of good sampling practice. Identify a random pattern of values using the 2/3 rule. Identify three different types of non-random patterns and interpret their meaning. Explain when a non-random pattern may be a sign of process improvement.