The XCHART statement creates cumulative sum control charts from subgroup means or individual measurements. You can create these charts for one-sided cusum (decision interval) schemes or for two-sided (V-mask) schemes. A one-sided scheme is designed to detect either a positive or a negative shift from the target mean, and a two-sided scheme is designed to detect positive and negative shifts from the target mean.
You can use options in the XCHART statement to
specify parameters for a decision interval or V-mask
specify the shift to be detected
specify the target mean
specify a known (standard) value for the process standard deviation or estimate the standard deviation from the data using various methods
tabulate the information displayed on the chart
save the information displayed on the chart in an output data set
read parameters for the cusum scheme from a data set
display a secondary chart that plots a time trend that has been removed from the data
add block legends and special symbol markers to reveal stratification in process data
superimpose stars at each point to represent related multivariate factors
display vertical and horizontal reference lines
modify the axis values and labels
modify the chart layout and appearance
You have three alternatives for producing cumulative sum control charts with the XCHART 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.