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SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

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1508 SPCHART<br />

• The default span (2) and sigma value (3) are used.<br />

• Since no BY variable is specified, the x axis is labeled by sequence numbers.<br />

TITLE, SUBTITLE, and FOOTNOTE Subcommands<br />

TITLE, SUBTITLE, and FOOTNOTE specify lines of text placed at the top or bottom of the control<br />

chart.<br />

• One or two lines of text can be specified for TITLE or FOOTNOTE, and one line of text can<br />

be specified for SUBTITLE.<br />

• Each line of text must be enclosed in apostrophes or quotation marks. The maximum<br />

length of any line is 72 characters.<br />

• The default font sizes and types are used for the title, subtitle, and footnote.<br />

• By default, the title, subtitle, and footnote are left-aligned with the y axis.<br />

• If you do not specify TITLE, the default title is Control Chart followed by the label of the<br />

process variable.<br />

• If you do not specify SUBTITLE, the subtitle provides the split-file information if split-file<br />

processing is in effect; otherwise it is null, which leaves more space for the chart.<br />

• If you do not specify FOOTNOTE, the sigma level is identified as the first line of the footnote.<br />

Example<br />

SPCHART TITLE = ’Wheel Production’<br />

/SUBTITLE = ’Process Control’<br />

/IR=SUBSIZE.<br />

XR and XS Subcommands<br />

XR produces an X-bar chart and an R chart. XS produces an X-bar chart and an s chart. X-bar,<br />

R, and s charts are control charts for continuous variables, such as size, weight, length, and<br />

temperature.<br />

An X-bar chart plots the mean of each subgroup. The center line indicates the mean of<br />

subgroup means. The control limits are calculated from subgroup means, numbers, standard<br />

deviations, and the user-specified SIGMA value (see “SIGMA Subcommand” on p. 1521).<br />

Figure 1 shows an X-bar chart.

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