See SHWMCHR in the SAS/QC Sample LibraryIn this example, the MCHART 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 Detergent
and create a summary data set named Dethist
:
proc shewhart data=Detergent; mchart Weight*Lot / outhistory = Dethist 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 17.34. Figure 17.37 contains a partial listing of Dethist
.
Figure 17.37: The Summary Data Set Dethist
Summary Data Set DETHIST for Detergent Box Weights |
Lot | WeightM | WeightR | WeightN |
---|---|---|---|
1 | 22.56 | 9.54 | 5 |
2 | 23.54 | 3.07 | 5 |
3 | 24.35 | 4.65 | 5 |
4 | 25.52 | 5.05 | 5 |
5 | 23.25 | 8.04 | 5 |
6 | 23.01 | 6.33 | 5 |
7 | 24.19 | 2.19 | 5 |
8 | 26.27 | 2.18 | 5 |
9 | 22.31 | 6.08 | 5 |
10 | 22.66 | 8.21 | 5 |
11 | 26.38 | 4.97 | 5 |
12 | 23.01 | 5.05 | 5 |
13 | 23.15 | 5.37 | 5 |
14 | 24.73 | 4.95 | 5 |
15 | 25.86 | 5.58 | 5 |
16 | 23.99 | 4.35 | 5 |
17 | 24.30 | 5.24 | 5 |
18 | 24.88 | 4.87 | 5 |
19 | 25.92 | 7.22 | 5 |
20 | 25.63 | 6.30 | 5 |
21 | 25.17 | 6.52 | 5 |
22 | 26.72 | 5.18 | 5 |
23 | 23.67 | 9.17 | 5 |
24 | 24.92 | 4.62 | 5 |
25 | 24.51 | 5.40 | 5 |
26 | 24.75 | 3.41 | 5 |
27 | 25.10 | 4.76 | 5 |
28 | 25.64 | 3.47 | 5 |
There are four variables in the data set Dethist
.
Lot
contains the subgroup index.
WeightM
contains the subgroup medians.
WeightR
contains the subgroup ranges.
WeightN
contains the subgroup sample sizes.
Note that the summary statistic variables are named by adding the suffix characters M, R, and N to the process Weight
specified in the MCHART statement. In other words, the variable naming convention for OUTHISTORY= data sets is the same as
that for HISTORY= data sets.
If you specify the STDDEVIATIONS option, the OUTHISTORY= data set includes a subgroup standard deviation variable instead of a subgroup range variable, as demonstrated by the following statements:
proc shewhart data=Detergent; mchart Weight*Lot / outhistory = Dethist2 stddeviations nochart; run;
Figure 17.38 contains a partial listing of Dethist2
.
Figure 17.38: The Summary Data Set Dethist2
Summary Data Set with Subgroup Standard Deviations |
Lot | WeightM | WeightS | WeightN |
---|---|---|---|
1 | 22.56 | 3.84205 | 5 |
2 | 23.54 | 1.34050 | 5 |
3 | 24.35 | 1.68087 | 5 |
4 | 25.52 | 2.11558 | 5 |
5 | 23.25 | 3.14747 | 5 |
6 | 23.01 | 2.37115 | 5 |
7 | 24.19 | 0.86491 | 5 |
8 | 26.27 | 0.88382 | 5 |
9 | 22.31 | 2.55563 | 5 |
10 | 22.66 | 3.20064 | 5 |
11 | 26.38 | 2.10858 | 5 |
12 | 23.01 | 1.85360 | 5 |
13 | 23.15 | 1.99936 | 5 |
14 | 24.73 | 1.96853 | 5 |
15 | 25.86 | 2.37425 | 5 |
16 | 23.99 | 1.77395 | 5 |
17 | 24.30 | 2.14006 | 5 |
18 | 24.88 | 1.98148 | 5 |
19 | 25.92 | 2.78591 | 5 |
20 | 25.63 | 2.51040 | 5 |
21 | 25.17 | 2.82905 | 5 |
22 | 26.72 | 2.05752 | 5 |
23 | 23.67 | 3.67124 | 5 |
24 | 24.92 | 1.96007 | 5 |
25 | 24.51 | 2.15219 | 5 |
26 | 24.75 | 1.35365 | 5 |
27 | 25.10 | 1.80968 | 5 |
28 | 25.64 | 1.38345 | 5 |
The variable WeightS
, which contains the subgroup standard deviations, is named by adding the suffix character S to the process Weight
.
For more information, see OUTHISTORY= Data Set.