Note: See Standard Deviation Chart (s Chart) Example in the SAS/QC Sample Library.
In this example, the SCHART statement is used to create a summary data set that can be read later by the SHEWHART procedure
(as in the preceding example). The following statements read measurements from the data set Turbine
and create a summary data set named Turbhist
:
proc shewhart data=Turbine; schart KWatts*Day / outhistory = Turbhist nochart; run;
The OUTHISTORY= option names the output data set, and the NOCHART option suppresses the display of the chart, which would be identical to the chart in Figure 17.78. Options such as OUTHISTORY= and NOCHART are specified after the slash (/) in the SCHART statement. A complete list of options is presented in the section Syntax: SCHART Statement.
Figure 17.81 contains a partial listing of Turbhist
.
Figure 17.81: The Summary Data Set Turbhist
Summary Data Set for Power Output |
Day | KWattsX | KWattsS | KWattsN |
---|---|---|---|
04JUL | 3487.40 | 220.260 | 20 |
05JUL | 3471.65 | 210.427 | 20 |
06JUL | 3488.30 | 147.025 | 20 |
07JUL | 3434.20 | 157.637 | 20 |
08JUL | 3475.80 | 258.949 | 20 |
There are four variables in the data set Turbhist
.
Day
contains the subgroup index.
KWattsX
contains the subgroup means.
KWattsS
contains the subgroup standard deviations.
KWattsN
contains the subgroup sample sizes.
The subgroup mean variable is included even though it is not required by the SCHART statement. This enables the data set
to be used as a HISTORY= data set with the BOXCHART, XCHART, and XSCHART statements, as well as with the SCHART statement.
Note that the summary statistic variables are named by adding the suffix characters X, S, and N to the process KWatts
specified in the SCHART statement. In other words, the variable naming convention for OUTHISTORY= data sets is the same as
that for HISTORY= data sets.
For more information, see OUTHISTORY= Data Set.