Attribute Charts Options - Layout Tab

Control Charts for Variables vs. Charts for Attributes

Select the Layout tab of the Options dialog box to access the options described here.

Chart layout

Include short and long variable names in titles

Select this check box to include the long variable name (if one exists) in the title of the chart.

Project header/Include project header line in titles

Select the Include project header line in titles check box to include the project header in the title of the chart; specify a title in the Project header box above this option. This header will be used to label the main graphs.

Note that the project header will not be saved, even when you request to save the specified Layout tab options as the default (by selecting the Set as default on OK check box). This ensures that all new project files will not have the same Project header.

Include histograms

When you select this check box, Statistica will include histograms of the sample statistics (X-bar and R/S for variability charts; P, C, Np, or U for attribute charts) in the chart.

Relative size of histogram

 This box is available only if the Include histograms check box is selected. Enter the preferred size of the histograms in this box, or adjust the size using the microscrolls.

Plot subset of samples in control charts and histograms from/to

Select these check boxes and click the down arrows to display a list where you can specify the subset of cases to plot; note that the numbers in the from and to boxes refer to the consecutive numbers of the samples, not to the actual codes (or dates) that were used in the grouping variable to identify to which sample each observation belongs.

plot last N samples only

Use this option to plot the last n samples only. It is particularly useful when you auto-update the chart by adding new samples (via some external data collection device). By setting this button, you can display a constant number of samples that will always include the newest (added) sample, and the N-1 preceding samples.

Show process specifications and specification limits in chart

Select this check box to include the process specifications and specification limits (USL, LSL) in the X-bar chart. This option is not available if the Options dialog was called from an attribute chart results dialog. After selecting this option, the chart will be updated using the specifications that have been defined on the Specs tab on the X-bar & R (S) Results dialog or the Moving Average Results dialog. Click the Process capability button on the Specs tab of the X-bar & R (S) Results dialog to set those specifications. For more information concerning the computation and interpretation of capability indices computed for variable control charts, refer to Process Analysis.

Compute runs tests (and identify out-of-control samples)

If this check box is selected, the samples in the graph that violate at least one of the selected runs tests will be highlighted in the graph. The runs tests are explained in the Introductory Overview - Out-Of-Control Process: Runs Tests. In short, these tests are designed to detect patterns that may indicate that the process is out of control. To customize the specific runs tests that are to be performed, click on the Runs tests button on the X-specs tab or the R/S-specs tab.

Add space in chart for N extra samples

This check box will affect the horizontal X-axis scaling of the chart, to make room for additional samples. This is particularly useful if one wants to print a chart with room for additional samples to be added later by hand. Use the microscrolls or type the number into the box.

Show breaks between non-consecutive samples

Select this check box to show breaks in the line denoting the successive samples. For example, suppose you were unable to collect sample 6 due to machine error. There is a break in consecutive samples at sample number 5 (sample 6 is missing). If you set the Show breaks... option, then the X-bar & R (S) charts will show a break in the line at sample 5; (the points denoting samples 5 and 7 will not be connected by a line).

Raw data in X-bar (X-MA) chart

Select this check box to plot the raw data points (for all samples) in the X-bar Chart. To include raw data points for a selected number of samples ( out-of-control points) select the Show individual observations check box on the Brushing tab of the results dialog. When you have selected this option, and you then turn on or off the display of raw data points for a single sample on the Brushing tab, the display raw data for all samples flag will be reset to zero. Note that this option is only available when an X-bar chart (or Moving Average chart) has been created; it is not available for X and Moving Range charts or for Attribute Charts.

Show moving average line on X-bar (X-MA) chart

Select this check box to plot a moving average line on the X-bar or attribute chart. A moving average line can be used to detect small trends across successive sample means. After selecting this option, click the Specify button to display the Specify Type of Moving Average dialog box. Note that this option is called Show moving average on Chart if selected from an attributes chart results dialog. If you choose to turn the moving average line on from the X-Specs tab in the results dialog box, this option will be automatically selected.

Include time-stamp in charts

Select this check box to include the time-stamp from the most recent chart update in the title of the graph. Note that this time is not taken from the data file but rather from the system, and it represents the last time the graph was updated (or created). To label the sample values with the time-stamp associated with each sample, use the Labeling of Samples and X-axis options available on the Labeling tab of the Options dialog box.

Include date-stamp in charts

Select this check box to include the date-stamp from the most recent chart update in the title of the graph. Note that this date is not taken from the data file but rather from the system, and it represents the last time the graph was updated (or created). To label the sample values with the date-stamp associated with each sample, use the Labeling of Samples and X-axis options available on the Labeling tab of the Options dialog box.

Identify sets of samples (with separate specs) in the chart

Select this check box to label sets of samples in the chart. If separate specifications have been established for each set of samples (see the Sets tab on the respective results dialog), the specifications used for that set will be shown (plotted) in the chart. For example, if the first set uses a pre-specified process mean of 10, and the second set uses the computed process mean, the center lines for the two sets will be different (one will be set at 10, the other will be set at the process mean).

Separate the parts with vertical lines

Select this check box in order to clearly identify samples belonging to different parts in the chart. This option is available only if parts were specified, and hence the current chart is a short-run chart.