IRCHART Statement: SHEWHART Procedure

Overview: IRCHART Statement

The IRCHART statement creates control charts for individual measurements and moving ranges. These charts are appropriate when only one measurement is available for each subgroup sample and when the measurements are independently and normally distributed.

You can use options in the IRCHART statement to

compute control limits from the data based on a multiple of the standard error of the individual measurements and moving ranges or as probability limits
tabulate individual measurements, moving ranges, and control limits
save control limits in an output data set
save individual measurements and moving ranges in an output data set
read preestablished control limits from a data set
apply tests for special causes (also known as runs tests and Western Electric rules)
specify a known (standard) process mean and standard deviation for computing control limits
specify the number of consecutive measurements to use when computing the moving ranges
display distinct sets of control limits for data from successive time phases
add block legends and symbol markers to reveal stratification in process data
superimpose stars at points to represent related multivariate factors
clip extreme points to make the chart more readable
display vertical and horizontal reference lines
control axis values and labels
control layout and appearance of the chart

You have three alternatives for producing charts of individual measurements and moving ranges with the IRCHART statement:

ODS Graphics output is produced if ODS Graphics is enabled, for example by specifying the ODS GRAPHICS ON statement prior to the PROC statement.
Otherwise, traditional graphics are produced by default if SAS/GRAPH^®is licensed.
Legacy line printer charts are produced when you specify the LINEPRINTER option in the PROC statement.

See Chapter 3: SAS/QC Graphics, for more information about producing these different kinds of graphs.