EWMA X-Bar and R or S Chart for Variables

Creates an exponentially weighted moving average (EWMA) and R or S quality control chart for each variable in the input descriptor continuous dependent Variable list. You can set the center line for the EWMA chart and sigma; also computes SixGraph summary and short-run charts.

 If no categorical variable is specified, the program will compute samples from a (user-defined) fixed number of consecutive observations. Short-run charts can also be computed; if a second categorical predictor variable is specified in the input descriptor, then that variable will be used to assign samples to parts; otherwise always k (as specified by the user) consecutive samples will be assigned to consecutive parts.

General

Element Name Description
Detail of computed results reported Detail of results reported; by default the respective chart summary is reported. If All results is requested, then spreadsheet summaries for each chart and outlier summaries are also computed and reported in results spreadsheets.
Type of EWMA chart Type of EWMA X-bar chart (how to estimate sigma)
Lambda for EWMA chart Parameter Lambda for computing the exponentially weighted moving average
Number of obs. per sample Number of observations per sample; each consecutive set of k observations will be assigned to the same sample; if a categorical predictor is specified, then the (first) categorical predictor variable will be used to assign observations to samples.
Min. n per sample Samples with less than k number of observations will be ignored (not included in charts)
Short run chart. Specifies whether the current chart is a short-run chart for multiple parts; if so, Statistica will either assign samples to parts based on the specified fixed number of samples per part, or take the second categorical predictor variable (if one is specified) to assign samples to parts.
Number of samples per part Number of samples per part (for short-run charts); if a second categorical predictor variable is specified, Statistica will determine the assignment of samples to parts from the integer codes found in that variable; otherwise the program will use this parameter to assign consecutive k samples to parts.

EWMA Chart Specs

Element Name Description
Applies user-defined centerline Applies user-defined centerline value for the EWMA chart; if false, compute the centerline value from the data (mean).
User-defined centerline value User-defined centerline value for EWMA chart.
Applies user-defined sigma Applies a user-defined value for sigma to the EWMA chart; if false, estimate sigma from the data (via R-bar or S-bar).
User-defined sigma value User-defined value of sigma (will automatically compute center line value for R/S chart).
Specify limits as Specify how to set (compute) the control and warning limits for the chart, i.e., in terms of multiples of Sigma, computed from probability values, or as a constant. Then set the values below accordingly.
Lower control limit EWMA Lower control limit for EWMA chart; specified either in multiples of sigma, as p value, or as a constant, depending on the setting of the Specify-limits-as option.
Upper control limit EWMA Upper control limit for EWMA chart; specify either in multiples of sigma, as p value, or as a constant, depending on the setting of the Specify-limits-as option.
Show warning lines (EWMA). Show warning lines in the EWMA chart.
Lower warning limit EWMA. Lower warning limit for EWMA chart; specify either in multiples of sigma, as p value, or as a constant, depending on the setting of the Specify-limits-as option.
Upper warning limit EWMA Upper warning limit for EWMA chart; specify either in multiples of sigma, as p value, or as a constant, depending on the setting of the Specify-limits-as option.

R/S Specs

Element Name Description
Specify limits as Specify how to set (compute) the control and warning limits for the chart, i.e., in terms of multiples of Sigma, computed from probability values, or as a constant. Then set the values below accordingly.
Lower control limit R/S Lower control limit for R or S chart; specify either in multiples of sigma (R/S), as p value, or as a constant, depending on the setting of the Specify-limits-as option.
Upper control limit R/S Upper control limit for R or S chart; specify either in multiples of sigma (R/S), as p value, or as a constant, depending on the setting of the Specify-limits-as option.
Show warning lines (R/S) Show warning lines in the R or S chart.
Lower warning limit R/S Lower warning limit for R or S chart; specify either in multiples of sigma (R/S), as p value, or as a constant, depending on the setting of the Specify-limits-as option.
Upper warning limit R/S Upper warning limit for R or S chart; specify either in multiples of sigma (R/S), as p value, or as a constant, depending on the setting of the Specify-limits-as option.

Process Capability

Element Name Description
Creates Cpk, Ppk, etc. Creates process capability and performance indices (summaries).
Type of specification limits Type of specification limits: Two-sided: Nominal plus/minus delta; Nominal, lower, Upper; One-sided: Lower, nominal; Nominal, upper.
Nominal value (for spec. limits) Nominal value, for process capability computations.
Delta value (for spec. limits) Value of delta, for defining specification limits as nominal plus/minus delta.
Lower specification limit Lower specification limit; not applicable if Type of specification limits is equal to Nominal Upper (one-sided).
Upper specification limit Upper specification limit; not applicable if Type of specification limits is equal to Lower Nominal (one-sided).

Displays

Element Name Description
Runs tests Select whether or not to compute runs tests, and if so, whether or not to indicate violations of runs tests in the charts.
Formats for values on axes Select how to determine the display format of scale (axis) labels in control charts; choose From variable formats to format the scale (axis) labels using the display format of the respective variable in the plot; use Number of digits to specify a fixed number of digits for the display format.
Number of digits for scale Specifies the number of digits for the display format, for scale (axis) labels in charts; this options is only applicable if the Formats for values on axes option is set to Number of digits.
Number of digits values Specifies the number of digits to be used for displaying numbers (values other than scale or axes values for charts) in various charts and results tables.
Process capability, n of digits Specifies the number of digits to be used for displaying process capability indices and related statistics.
Separate parts in charts If true, consecutive samples belonging to different parts (in short-run charts) will be separated by vertical lines; not applicable for standard (non short-run) charts.
Label parts in charts If true, samples belonging to different parts (in short-run charts) will be labeled with the part names; not applicable for standard (non short-run) charts.