Saving Summary Statistics

SCHART Statement

Saving Summary Statistics

See SHWSCHR 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:

   title 'Summary Data Set for Power Output';
   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 40.2. Options such as OUTHISTORY= and NOCHART are specified after the slash (/) in the SCHART statement. A complete list of options is presented in the "Syntax" section.

Figure 40.5 contains a listing of 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
09JUL	3518.10	211.566	20
10JUL	3492.65	193.779	20
11JUL	3496.40	212.024	20
12JUL	3398.50	199.201	20
13JUL	3456.05	173.455	20
14JUL	3493.60	187.465	20
15JUL	3563.30	205.472	20
16JUL	3519.05	173.676	20
17JUL	3474.20	200.576	20
18JUL	3443.60	222.084	20
19JUL	3586.35	185.724	20
20JUL	3486.45	223.474	20
21JUL	3492.90	145.267	20
22JUL	3432.80	190.994	20
23JUL	3496.90	208.858	20

Figure 40.5: The Summary Data Set TURBHIST

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 allows 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" .

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