XCHART 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 4.23: OUTLIMITS= Data Set

Variable

Description

_ALPHA_

significance level ($\alpha $).

_DFE_

degrees of freedom for mean square error ($\nu $).

_GROUP_

group-variable specified in the XCHART statement

_INDEX_

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

_LDLX_

lower decision limit for group means

_LIMITK_

number of groups

_LIMITN_

group sample size associated with the decision limits

_MEAN_

weighted average of group means ($\overline{\overline{X}}$)

_MSE_

mean square error ($\widehat{\sigma ^2}$).

_TYPE_

type (estimate or standard value) of _MEAN_ and _MSE_

_UDLX_

upper decision limit for group means

_VAR_

response specified in the XCHART statement


Notes:

  1. In the unbalanced case, the special missing value V is assigned to the variables _LIMITN_, _LDLX_, and _UDLX_ to indicate that the decision limits vary with the group sample size.

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

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

OUTSUMMARY= Data Set

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

  • the group-variable

  • a group mean variable named by response suffixed with X

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

  • a group standard deviation variable named by response suffixed with S

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 XCHART statement. For example, consider the following statements: 

proc anom data=Steel;
   xchart (Width Diameter)*Lot / outsummary=Summary;
run;

The data set Summary contains variables named Lot, WidthX, WidthS, WidthN, DiameterX, DiameterS, and DiameterN. 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 the section Saving Summary Statistics for Groups.

OUTTABLE= Data Set

The OUTTABLE= data set saves group summary statistics, decision limits, and related information. The following variables can be saved:

Variable

Description

_ALPHA_

significance level ($\alpha $)

_EXLIM_

decision limit exceeded (if any)

group

values of the group variable

_LDLX_

lower decision limit for group mean

_LIMITN_

nominal sample size associated with the decision limits

_MEAN_

central line

_SUBN_

group sample size

_SUBX_

group mean

_UDLX_

upper decision limit for group mean

_VAR_

response specified in the XCHART 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 the section Saving Decision Limits.