When you save the parameters for the cusum scheme in an OUTLIMITS= data set, the following variables are included:
Table 6.5: OUTLIMITS= Data Set
Variable 
Description 


probability () of Type 1 error 

average run length for zero shift 

average run length for shift of 

probability () of Type 2 error 

shift () to be detected 

decision interval h for onesided scheme; distance h between origin and upper arm Vmask for twosided scheme 

headstart value 

optional identifier for cusum parameters (if the OUTINDEX= option is specified) 

reference value k for onesided scheme; slope of lower Vmask arm for twosided scheme 

nominal sample size for cusum scheme 

estimated process mean () 

target mean 

origin of Vmask 

type of scheme ('ONESIDED' or 'TWOSIDED') 



estimated or known standard deviation ( or ) 

subgroupvariable specified in XCHART statement 

type ('ESTIMATE' or 'STANDARD') of 

process specified in XCHART statement 
Notes:
If the subgroup sample sizes vary, the special missing value V is assigned to the variable _LIMITN_
.
If a Vmask is specified with SIGMAS=k, _ALPHA_
is computed as , where is the standard normal distribution function.
If a Vmask is specified with ALPHA=, _SIGMAS_
is computed as , where is the inverse standard normal distribution function.
BY variables are saved in the OUTLIMITS= data set.
The OUTLIMITS= data set contains one observation for each process specified in the XCHART statement. For an example, see Saving Cusum Scheme Parameters.
When you save subgroup summary statistics in an OUTHISTORY= data set, the following variables are included:
the subgroupvariable
a subgroup mean variable named by process suffixed with X
a subgroup sample size variable named by process suffixed with N
a subgroup standard deviation variable named by process suffixed with S
a cusum variable named by process suffixed with C
Given a process 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.
Variables containing subgroup summary statistics are created for each process specified in the XCHART statement. For example, consider the following statements:
proc cusum data=Steel limits=Stparm; xchart (Width Diameter)*Lot / outhistory=Summary; run;
The data set Summary
would contain nine variables named Lot
, WidthX
, WidthS
, WidthN
, WidthC
, DiameterX
, DiameterS
, DiameterN
, and DiameterC
.
Additionally, if specified, the following variables are included:
BY variables
blockvariables
symbolvariable
ID variables
_PHASE_
(if the OUTPHASE= option is specified)
For an example creating an OUTHISTORY= data set, see Saving Summary Statistics.
The OUTTABLE= data set saves subgroup means, subgroup sample sizes, cusums, and cusum limits. The following variables are included:
Variable 
Description 


cumulative sum 

decision interval or Vmask arm exceeded 

decision interval 

lower arm of Vmask 

upper arm of Vmask 
subgroup 
values of the subgroup variable 

subgroup sample size 

subgroup mean 

subgroup standard deviation 

process specified in XCHART statement 
In addition, the following variables are saved if specified:
BY variables
blockvariables
ID variables
_PHASE_
(if the READPHASES= option is specified)
_TREND_
(if the TRENDVAR= option is specified)
symbolvariable
Note that the variables _VAR_
and _EXLIM_
are character variables of length eight. The variable _PHASE_
is a character variable of length 16.