Output Data Sets

MACHART Statement

Output Data Sets

OUTLIMITS= Data Set

The OUTLIMITS= data set saves the control limit parameters. The following variables can be saved:

Variable Description

_ALPHA_ probability ( $\alpha$ ) of exceeding limits

_INDEX_ optional identifier for the control limits specified with the OUTINDEX= option

_LIMITN_ sample size associated with the control limits

_MEAN_ process mean ( $\overline{\overline{X}}$ or $\mu_{0}$ )

_SIGMAS_ multiple (k) of standard error of A_i

_SPAN_ number of terms in the moving average

_STDDEV_ process standard deviation ( $\hat{\sigma}$ or $\sigma_{0}$ )

_SUBGRP_ subgroup-variable specified in the MACHART statement

_TYPE_ type (estimate or standard value) of _MEAN_ and _STDDEV_

_VAR_ process specified in the MACHART statement

The OUTLIMITS= data set does not contain the control limits; instead, it contains control limit parameters that can be used to recompute the control limits.

Notes:

If the control limits vary with subgroup sample size, the special missing value V is assigned to the variable _LIMITN_.
If the limits are defined in terms of a multiple k of the standard error of A_i, the value of _ALPHA_ is computed as $\alpha=2(1-\Phi(k))$ , where $\Phi(\cdot)$ is the standard normal distribution function.
If the limits are probability limits, the value of _SIGMAS_ is computed as $k=\Phi^{-1}(1-\alpha/2)$ , where $\Phi^{-1}$ is the inverse standard normal distribution function.
Optional BY variables are saved in the OUTLIMITS= data set.

The OUTLIMITS= data set contains one observation for each process specified in the MACHART statement.

You can use OUTLIMITS= data sets

to keep a permanent record of the control limit parameters
to write reports. You may prefer to use OUTTABLE= data sets for this purpose.
as LIMITS= data sets in subsequent runs of PROC MACONTROL

For an example of an OUTLIMITS= data set, see "Saving Control Limit Parameters" .

OUTHISTORY= Data Set

The OUTHISTORY= data set saves subgroup summary statistics. The following variables can be saved:

the subgroup-variable
a subgroup mean variable named by process suffixed with X
a subgroup standard deviation variable named by process suffixed with S
a subgroup moving average variable named by process suffixed with A
a subgroup sample size variable named by process suffixed with N

Given a process name that contains eight characters, the procedure first shortens the name to its first four characters and its last three characters, and then it adds the suffix. For example, the procedure shortens the process DIAMETER to DIAMTER before adding the suffix.

Subgroup summary variables are created for each process specified in the MACHART statement. For example, consider the following statements:

   proc macontrol data=clips;
      machart (gap yldstren)*day / span      =3
                                   outhistory=cliphist;
   run;

The data set CLIPHIST would contain nine variables named DAY, GAPX, GAPS, GAPA, GAPN, YLDSRENX, YLDSRENS, YLDSRENA, and YLDSRENN.

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 OUTHISTORY= data set, see "Saving Summary Statistics" .

OUTTABLE= Data Set

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

Variable Description

_ALPHA_ probability ( $\alpha$ ) of exceeding control limits

_EXLIM_ control limit exceeded on moving average chart

_LCLA_ lower control limit for moving average

_LIMITN_ nominal sample size associated with the control limits

_MEAN_ process mean

_SIGMAS_ multiple (k) of the standard error associated with control limits

_SPAN_ number of terms in the moving average

subgroup values of the subgroup variable

_SUBN_ subgroup sample size

_SUBS_ subgroup standard deviation

_SUBX_ subgroup mean

_UCLA_ upper control limit for moving average

_UWMA_ uniformly weighted moving average

_VAR_ process specified in MACHART statement

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

BY variables
block-variables
ID variables
_PHASE_ (if the READPHASES= option is specified)
symbol-variable

Notes:

Either the variable_ALPHA_ or the variable _SIGMAS_ is saved depending on how the control limits are defined (with the ALPHA= or SIGMAS= options, respectively; or with the corresponding variables in a LIMITS= data set).
The variables _VAR_ and _EXLIM_ are character variables of length 8. The variable _PHASE_ is a character variable of length 16. All other variables are numeric.

For an example of an OUTTABLE= data set, see "Saving Control Limit Parameters" .

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Variable	Description
_ALPHA_	probability ( $\alpha$ ) of exceeding limits
_INDEX_	optional identifier for the control limits specified with the OUTINDEX= option
_LIMITN_	sample size associated with the control limits
_MEAN_	process mean ( $\overline{\overline{X}}$ or $\mu_{0}$ )
_SIGMAS_	multiple (k) of standard error of A_i
_SPAN_	number of terms in the moving average
_STDDEV_	process standard deviation ( $\hat{\sigma}$ or $\sigma_{0}$ )
_SUBGRP_	subgroup-variable specified in the MACHART statement
_TYPE_	type (estimate or standard value) of _MEAN_ and _STDDEV_
_VAR_	process specified in the MACHART statement