MRCHART Statement: SHEWHART Procedure
| Overview: MRCHART Statement |
The MRCHART statement creates charts for subgroup medians and ranges, which are used to analyze the central tendency and variability of a process.
You can use options in the MRCHART statement to
compute control limits from the data based on a multiple of the standard error of the plotted medians and ranges or as probability limits
tabulate subgroup sample sizes, subgroup medians, subgroup ranges, control limits, and other information
save control limits in an output data set
save subgroup sample sizes, subgroup medians, and subgroup 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 the method for estimating the process standard deviation
specify a known (standard) process mean and standard deviation for computing control limits
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 charts 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 medians and ranges with the MRCHART 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.