You can read summary statistics, decision limits, and outlier values from a BOX= data set specified in the PROC ANOM statement. This enables you to reuse an OUTBOX= data set created in a previous run of the ANOM procedure to display a box chart.
A BOX= data set must contain the following variables:
the group variable
_VAR_
, containing the analysis variable name
_TYPE_
, identifying features of boxandwhisker plots
_VALUE_
, containing values of those features
Each observation in a BOX= data set records the value of a single feature of one group’s boxandwhisker plot, such as its
mean. The _TYPE_
variable identifies the feature whose value is recorded in a given observation. The following table lists valid _TYPE_
variable values:
Table 4.7: Valid _TYPE_ Values in a BOX= Data Set
_TYPE_ Value 
Description 

N 
group size 
ALPHA 
significance level 
LIMITN 
nominal sample size associated with decision limits 
LDLX 
lower decision limit for group mean 
UDLX 
upper decision limit for group mean 
RESPMEAN 
overall response variable mean 
MIN 
group minimum value 
Q1 
group first quartile 
MEDIAN 
group median 
MEAN 
group mean 
Q3 
group third quartile 
MAX 
group maximum value 
LOW 
low outlier value 
HIGH 
high outlier value 
LOWHISKR 
low whisker value, if different from MIN 
HIWHISKR 
high whisker value, if different from MAX 
FARLOW 
low far outlier value 
FARHIGH 
high far outlier value 
The features identified by _TYPE_
values N, LDLX, UDLX, RESPMEAN, MIN, Q1, MEDIAN, MEAN, Q3, and MAX are required for each group.
Other variables that can be read from a BOX= data set include:
the variable _ID_
, containing labels for outliers
the variable _HTML_
, containing links to be associated with features on box plots
blockvariables
symbolvariable
BY variables
ID variables
When you specify one of the keywords SCHEMATICID or SCHEMATICIDFAR with the BOXSTYLE= option, values of _ID_
are used as outlier labels. If _ID_
does not exist in the BOX= data set, the values of the first variable listed in the ID statement are used.
You can read raw data (response values) from a DATA= data set specified in the PROC ANOM statement. Each response specified in the BOXCHART 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 BOXCHART 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 Creating ANOM Boxcharts 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 4.4. 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:
the variables _LDLX_
, _MEAN_
, and _UDLX_
, which specify the decision limits directly
the variables _MEAN_
, _MSE_
, and _DFE_
, 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 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 BOXCHART statement must contain the following:
the groupvariable
a group minimum variable for each response
a group firstquartile variable for each response
a group mean variable for each response
a group median variable for each response
a group thirdquartile variable for each response
a group maximum variable for each response
a group standard deviation variable for each response
a group sample size variable for each response
The names of the group summary statistics variables must be the response name concatenated with the following special suffix characters:
Group Summary Statistic 
Suffix Character 

group minimum 
L 
group firstquartile 
1 
group median 
M 
group mean 
X 
group thirdquartile 
3 
group maximum 
H 
group standard deviation 
S 
group sample size 
N 
For example, consider the following statements:
proc anom summary=Summary; xchart (Weight Yieldstrength)*Batch; run;
The data set Summary
must include the variables Batch
, WeightL
, Weight1
, WeightX
, WeightM
, Weight3
, WeightH
, WeightS
, WeightN
, YieldstrengthL
, Yieldstrength1
, YieldstrengthX
, YieldstrengthM
, Yieldstrength3
, YieldstrengthH
, 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 Creating ANOM Boxcharts 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 BOXCHART statement:
Table 4.8: 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 maximum 

group median 

group minimum 

group sample size 

group first quartile 

group third quartile 

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 Saving Decision Limits.