Saving Summary Statistics
See SHWSCHR in the SAS/QC Sample Library
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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 |
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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" .
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.