The SPC Procedure

The EWMACHART statement produces exponentially weighted moving average (EWMA) charts of subgroup means. Table 3 lists the options that you can specify in an EWMACHART statement. For detailed descriptions of these options, see the section Dictionary of Options.

Table 3: EWMACHART Statement Options

Option	Description
ALLN	Includes all subgroups in the analysis, regardless of sample size
ASYMPTOTIC	Requests constant control limits
EXCHART	Produces results only for charts in which exceptions occur
LIMITN=	Specifies the nominal sample size for fixed control limits
NOPRINT	Suppresses ODS output
OUTLIMITS=	Creates an output data table that contains control limit parameters
OUTTABLE=	Creates an output data table that contains subgroup summary statistics and control limits
RESET	Resets the value of the EWMA after each point outside the control limits
SIGMAS=	Specifies the width of the control limits in terms of a multiple of the standard error of the EWMAs
SMETHOD=	Specifies the method of estimating the process standard deviation
WEIGHT=	Specifies the weight to assign to the most recent subgroup mean in the computation of the EWMA