Overview
The SCHART statement creates an s chart
for subgroup standard deviations, which is
used to analyze the variability of a process.*
You can use options in the SCHART statement to
- compute control limits from the data based on a multiple of
the standard error of the plotted standard deviations or
as probability limits
- tabulate subgroup sample sizes,
subgroup standard deviations, control limits, and other
information
- save control limits in an output data set
- save subgroup sample sizes, subgroup means,
and subgroup standard deviations in an output data set
- read preestablished control limits from a data set
- specify a method for estimating the process
standard deviation
- specify a known (standard) process 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 chart more readable
- display vertical and horizontal reference lines
- control axis values and labels
- control layout and appearance of the chart
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
