PCHART Statement: ANOM Procedure

Output Data Sets

OUTLIMITS= Data Set

The OUTLIMITS= data set saves decision limits and decision limit parameters. The following variables can be saved:

Table 4.13: OUTLIMITS= Data Set

Variable

Description

_ALPHA_

Significance level ($\alpha $)

_GROUP_

Group-variable specified in the PCHART statement

_INDEX_

Optional identifier for the decision limits specified with the OUTINDEX= option

_LDLP_

Lower decision limit for proportions

_LIMITK_

Number of groups

_LIMITN_

Nominal sample size associated with the decision limits

_P_

Average proportion of nonconforming items ($\bar{p}$)

_TYPE_

Type (standard or estimate) of _P_

_UDLP_

Upper decision limit for proportions

_VAR_

Response specified in the PCHART statement


Notes:

  1. If the decision limits vary with group sample size, the special missing value V is assigned to the variables _LIMITN_, _LDLP_, and _UDLP_.

  2. A group must have at least one nonmissing value ($n_{i} \geq 1$), and there must be at least one group with $n_{i} \geq 2$.

  3. Optional BY variables are saved in the OUTLIMITS= data set.

The OUTLIMITS= data set contains one observation for each response specified in the PCHART statement. For an example, see Saving Decision Limits.

OUTSUMMARY= Data Set

The OUTSUMMARY= data set saves group summary statistics. The following variables are saved:

  • the group-variable

  • a group proportion variable named by response suffixed with P

  • a group sample size variable named by response suffixed with N

Given a response name that contains 32 characters, the procedure first shortens the name to its first 16 characters and its last 15 characters, and then it adds the suffix.

Group summary variables are created for each response specified in the PCHART statement. For example, consider the following statements: 

proc anom data=Input;
   pchart (Rework Rejected)*Batch / outsummary=Summary
                                    groupn =30;
run;

The data set Summary contains variables named Batch, ReworkP, ReworkN, RejetedP, and RejetedN.

Additionally, the following variables, if specified, are included:

  • BY variables

  • block-variables

  • symbol-variable

  • ID variables

  • _PHASE_ (if the OUTPHASE= option is specified)

For an example of an OUTSUMMARY= data set, see Saving Group Proportions.

Note that an OUTSUMMARY= data set created with the PCHART statement can be reused as a SUMMARY= data set.

OUTTABLE= Data Set

The OUTTABLE= data set saves group summary statistics, decision limits, and related information. Table 4.14 lists the variables that are saved:

Table 4.14: OUTTABLE= Data Set Variables

Variable

Description

_ALPHA_

Significance level ($\alpha $)

_EXLIM_

Decision limit exceeded on p chart

Group

Values of the group variable

_LDLP_

Lower decision limit for proportions

_LIMITN_

Nominal sample size associated with the decision limits

_SUBP_

Group proportion

_SUBN_

Group sample size

_UDLP_

Upper decision limit for proportions

_VAR_

Response specified in the PCHART statement


In addition, the following variables, if specified, are included:

  • BY variables

  • block-variables

  • symbol-variable

  • ID variables

  • _PHASE_ (if the READPHASES= option is specified)

Note: The variable _EXLIM_ is a character variable of length 8. The variable _PHASE_ is a character variable of length 48. The variable _VAR_ is a character variable whose length is no greater than 32. All other variables are numeric.

For an example, see Saving Decision Limits.