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SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

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858 MANOVA: Univariate<br />

partial η 2<br />

=<br />

( ssh)<br />

⁄ ( ssh + sse)<br />

where ssh is the hypothesis sum of squares and sse is the error sum of squares. The measure<br />

is an overestimate of the actual effect size. However, it is consistent and is applicable<br />

to all F tests and t tests. For a discussion of effect size measures, see Cohen (1977) or<br />

Hays (1981).<br />

CINTERVAL Subcommand<br />

CINTERVAL requests simultaneous confidence intervals for each parameter estimate and<br />

regression coefficient. MANOVA provides either individual or joint confidence intervals at<br />

any desired confidence level. You can compute joint confidence intervals using either<br />

Scheffé or Bonferroni intervals. Scheffé intervals are based on all possible contrasts, while<br />

Bonferroni intervals are based on the number of contrasts actually made. For a large number<br />

of contrasts, Bonferroni intervals will be larger than Scheffé intervals. Timm (1975) provides<br />

a good discussion of which intervals are best for certain situations. Both Scheffé and Bonferroni<br />

intervals are computed separately for each term in the design. You can request only<br />

one type of confidence interval per design.<br />

The following keywords are available on the CINTERVAL subcommand. If the subcommand<br />

is specified without any keyword, CINTERVAL automatically displays individual<br />

univariate confidence intervals at the 0.95 level.<br />

INDIVIDUAL(a) Individual confidence intervals. Specify the desired confidence level<br />

in parentheses following the keyword. The desired confidence level<br />

can be any decimal number between 0 and 1. When individual intervals<br />

are requested, BONFER and SCHEFFE have no effect.<br />

JOINT(a) Joint confidence intervals. Specify the desired confidence level in<br />

parentheses after the keyword. The default is 0.95. The desired confidence<br />

level can be any decimal number between 0 and 1.<br />

UNIVARIATE(type) Univariate confidence interval. Specify either SCHEFFE for Scheffé<br />

intervals or BONFER for Bonferroni intervals in parentheses after the<br />

keyword. The default specification is SCHEFFE.<br />

PLOT Subcommand<br />

MANOVA can display a variety of plots useful in checking the assumptions needed in the<br />

analysis. Plots are produced only once in the MANOVA procedure, regardless of how many<br />

DESIGN subcommands you enter. Use the following keywords on the PLOT subcommand<br />

to request plots. If the PLOT subcommand is specified by itself, the default is BOXPLOT.<br />

BOXPLOTS Boxplots. Plots are displayed for each continuous variable (dependent or<br />

covariate) named on the MANOVA variable list. Boxplots provide a simple<br />

graphical means of comparing the cells in terms of mean location and spread.<br />

The data must be stored in memory for these plots; if there is not enough<br />

memory, boxplots are not produced and a warning message is issued. This is<br />

the default if the PLOT subcommand is specified without a keyword.

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