Saving Summary Statistics

RCHART Statement

Saving Summary Statistics

See SHWRCHR in the SAS/QC Sample Library

In this example, the RCHART statement procedure 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 DISKS and create a summary data set named DISKHIST:

   title 'Summary Data Set for Disk Times';
   proc shewhart data=disks;
      rchart time*lot / outhistory = diskhist
                        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 39.2. Options such as OUTHISTORY= and NOCHART are specified after the slash (/) in the RCHART statement. A complete list of options is presented in the "Syntax" section.

Figure 39.5 contains a listing of DISKHIST.

Summary Data Set for Disk Times

lot	timeX	timeR	timeN
1	8.00833	0.16	6
2	8.02167	0.09	6
3	7.97833	0.07	6
4	8.00667	0.10	6
5	8.01833	0.16	6
6	8.00667	0.12	6
7	7.98500	0.15	6
8	8.03000	0.11	6
9	8.03000	0.15	6
10	7.99167	0.10	6
11	7.98833	0.10	6
12	7.98500	0.09	6
13	7.98833	0.13	6
14	8.00167	0.10	6
15	7.98333	0.13	6
16	8.01833	0.09	6
17	8.00833	0.11	6
18	7.98667	0.20	6
19	7.98667	0.18	6
20	8.01500	0.10	6
21	7.99000	0.14	6
22	8.01833	0.20	6
23	8.00833	0.11	6
24	7.98500	0.06	6
25	8.03667	0.15	6

Figure 39.5: The Summary Data Set DISKHIST

There are four variables in the data set DISKHIST.

LOT contains the subgroup index.
TIMEX contains the subgroup means.
TIMER contains the subgroup ranges.
TIMEN contains the subgroup sample sizes.

The subgroup mean variable is included in the OUTHISTORY= data set even though it is not required by the RCHART statement. This allows the data set to be used as a HISTORY= data set with the BOXCHART, XCHART, and XRCHART statements, as well as with the RCHART statement. Note that the summary statistic variables are named by adding the suffix characters X, R, and N to the process TIME specified in the RCHART 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" .

Chapter Contents
Previous
Next
Top