Interpretation & Calculations
An X-bar & Range Chart with process capability estimates from SPC IV Excel software.
X-bar & Range Charts are a set of control charts for variables data (data that is both quantitative and continuous in measurement, such as a measured dimension or time). The X-bar chart monitors the process location over time, based on the average of a series of observations, called a subgroup. The Range chart monitors the variation between observations in the subgroup over time. Range Chart and X-bar chart software from Quality America allows for simple SPC analysis.
Learn more about the SPC principles and tools for process improvement in Statistical Process Control Demystified (2011, McGraw-Hill) by Paul Keller, in his online SPC Concepts short course, or his online SPC certification course.