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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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SPAN Subcommand<br />

SPCHART 1521<br />

SPAN specifies the span from which the moving range for an individuals chart is calculated.<br />

The specification must be an integer value greater than 1. The default is 2. SPAN applies only<br />

to I and IR chart specifications.<br />

Example<br />

SPCHART /IR=SUBSIZE /SPAN=5.<br />

• The SPAN subcommand specifies that the moving ranges are computed from every five<br />

individual samples.<br />

CONFORM and NONCONFORM Subcommands<br />

Either CONFORM or NONCONFORM is required when you specify a status variable on the P<br />

or NP subcommand. That occurs when data are organized so that each case is an inspection<br />

unit (see “P and NP Subcommands” on p. 1513).<br />

• Either subcommand requires a value specification. The value can be numeric or string.<br />

String values must be enclosed within apostrophes.<br />

• If CONFORM is specified, all values for the status variable other than the value specified<br />

are tabulated as nonconformities. If NONCONFORM is specified, only the specified value<br />

is tabulated as nonconformities.<br />

• CONFORM and NONCONFORM apply only to P and NP chart specifications.<br />

SIGMA Subcommand<br />

SIGMA allows you to define the sigma level for a control chart. The value specified on SIGMA<br />

is used in calculating the upper and lower control limits on the chart. You can specify a number<br />

larger than 1 but less than or equal to 10. The larger the SIGMA value, the greater the range<br />

between the upper and the lower control limits. The default is 3.<br />

MINSAMPLE Subcommand<br />

MINSAMPLE specifies the minimum sample size for X-bar, R, or s charts. When you specify<br />

XR or XS on SPCHART, any subgroup with a size smaller than that specified on MINSAMPLE<br />

is excluded from the chart and from all computations. If each case is a subgroup, there must<br />

be at least as many variables named as the number specified on MINSAMPLE. The default is 2.<br />

LSL and USL Subcommand<br />

LSL and USL allow you to specify fixed lower and upper control limits. Fixed control limits<br />

are often used in manufacturing processes as designer-specified limits. These limits are displayed<br />

on the chart along with the calculated limits. If you do not specify LSL and USL, no

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