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 groupvariable. The groupvariable, 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 groupvariable. If the ith group contains items, there should be consecutive observations for which the value of the groupvariable 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
_PHASE_
(if the READPHASES= option is specified)
blockvariables
symbolvariable
BY variables
ID variables
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:
the variables _LDLX_
, _MEAN_, and _UDLX_
, which specify the decision limits directly
the variables _MEAN_
and _MSE_
, with _DFE_
recommended, which are used to calculate the decision limits according to the equations in the section Decision Limits
In addition, note the following:
The variables _VAR_
and _GROUP_
are always required. These must be character variables whose lengths are no greater than 32.
_DFE_
is optional. The default is , and in the case of equal group sizes, .
_MSE_
is optional if _LDLX_
and _UDLX_
are specified; otherwise it is required.
_LDLX_
and _UDLX_
must be specified together; otherwise their values are computed.
_ALPHA_
is optional but is recommended in order to maintain a complete set of decision limit information. The default value is 0.05.
_LIMITK_
is optional. The default value is k, the number of groups. A group must have at least one nonmissing value () and there must be at least one group with . If specified, _LIMITK_
overrides the value of k.
_LIMITN_
is optional. The default value is the common group size (n), in the balanced case . If specified, _LIMITN_
overrides the value of n.
The variable _TYPE_
is optional, but is recommended to maintain a complete set of decision limit information. The variable _TYPE_
must be a character variable of length 8. Valid values are 'ESTIMATE,' 'STANDARD,' 'STDMEAN,' and 'STDRMS.' The default is
'ESTIMATE.'
The variable _INDEX_
is required if you specify the READINDEX= option; this must be a character variable whose length is no greater than 48.
BY variables are required if specified with a BY statement.
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 groupvariable
a group mean variable for each response
a group sample size variable for each response
a group standard deviation variable for each response
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
_PHASE_
(if the READPHASES= option is specified)
blockvariables
symbolvariable
BY variables
ID variables
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:
Table 4.26: Variables Required in a TABLE= Data Set
Variable 
Description 

groupvariable 
values of the groupvariable 

lower decision limit for mean 

nominal sample size associated with the decision limits 

central line 

group sample size 

group mean 

upper decision limit for mean 
Other variables that can be read from a TABLE= data set include
blockvariables
symbolvariable
BY variables
ID variables
_PHASE_
(if the READPHASES= option is specified). This variable must be a character variable whose length is no greater than 48.
_VAR_
. This variable is required if more than one response is specified or if the data set contains information for more than one response. This variable must be a character variable whose length is no greater than 32.
For an example of a TABLE= data set, see the section Saving Decision Limits.