XCHART Statement: ANOM Procedure

You can read raw data (response values) from a DATA= data set specified in the PROC ANOM statement. Each response specified in the XCHART statement must be a SAS variable in the DATA= data set. This variable provides measurements that must be grouped into group samples indexed by the group-variable. The group-variable, which is specified in the XCHART statement, must also be a SAS variable in the DATA= data set. Each observation in a DATA= data set must contain a value for each response and a value for the group-variable. If the ith group contains items, there should be consecutive observations for which the value of the group-variable is the index of the ith group. For example, if each group contains five items and there are 10 groups, the DATA= data set should contain 50 observations.

Other variables that can be read from a DATA= data set include

By default, the ANOM procedure reads all of the observations in a DATA= data set. However, if the data set includes the variable _PHASE_, you can read selected groups of observations (referred to as phases) with the READPHASES= option.

For an example of a DATA= data set, see the section Creating ANOM Charts for Means from Response Values.

You can read preestablished decision limits (or parameters from which the decision limits can be calculated) from a LIMITS= data set specified in the PROC ANOM statement. For example, the following statements read decision limit information from the data set Conlims:

proc anom data=Info limits=Conlims;
   xchart Weight*Batch;
run;

The LIMITS= data set can be an OUTLIMITS= data set that was created in a previous run of the ANOM procedure. Such data sets always contain the variables required for a LIMITS= data set; see Table 4.23. The LIMITS= data set can also be created directly using a DATA step. When you create a LIMITS= data set, you must provide one of the following minimal combinations of variables:

In addition, note the following:

You can read group summary statistics from a SUMMARY= data set specified in the PROC ANOM statement. This enables you to reuse OUTSUMMARY= data sets that have been created in previous runs of the ANOM procedure or to read output data sets created with SAS summarization procedures, such as PROC MEANS.

A SUMMARY= data set used with the XCHART statement must contain the following:

The names of the group mean, group range, and group sample size variables must be the response name concatenated with the suffix characters X, S, and N, respectively.

For example, consider the following statements:

proc anom summary=Summary;
   xchart (Weight Yieldstrength)*Batch;
run;

The data set Summary must include the variables Batch, WeightX, WeightS, WeightN, YieldstrengthX, YieldstrengthS, and YieldstrengthN. Note that if you specify a response name that contains 32 characters, the names of the summary variables must be formed from the first 16 characters and the last 15 characters of the response name, suffixed with the appropriate character.

Other variables that can be read from a SUMMARY= data set include

By default, the ANOM procedure reads all of the observations in a SUMMARY= data set. However, if the data set includes the variable _PHASE_, you can read selected groups of observations (referred to as phases) by specifying the READPHASES= option.

For an example of a SUMMARY= data set, see the section Creating ANOM Charts for Means from Group Summary Data.

You can read summary statistics and decision limits from a TABLE= data set specified in the PROC ANOM statement. This enables you to reuse an OUTTABLE= data set created in a previous run of the ANOM procedure. Because the ANOM procedure simply displays the information in a TABLE= data set, you can use TABLE= data sets to create specialized ANOM charts.

The following table lists the variables required in a TABLE= data set used with the XCHART statement:

Other variables that can be read from a TABLE= data set include

For an example of a TABLE= data set, see the section Saving Decision Limits.