CINTERVAL Subcommand (MANOVA: Univariate command)
CINTERVAL requests simultaneous confidence intervals for each parameter estimate
and regression coefficient. MANOVA provides either individual or joint confidence intervals at any
desired confidence level. You can compute joint confidence intervals
that are using either Scheffé or Bonferroni intervals. Scheffé
intervals are based on all possible contrasts, while Bonferroni intervals
are based on the number of contrasts that are actually made. For a
large number of contrasts, Bonferroni intervals will be larger than
Scheffé intervals. Timm 1 provides
a good discussion of which intervals are best for certain situations.
Both Scheffé and Bonferroni intervals are computed separately
for each term in the design. You can request only one type of confidence
interval per design.
The following keywords are available on the CINTERVAL subcommand. If the subcommand
is specified without any keyword, CINTERVAL automatically displays individual univariate confidence intervals
at the 0.95 level.
INDIVIDUAL(a). Individual
confidence intervals. Specify the desired confidence level
in parentheses following the keyword. The desired confidence level
can be any decimal number between 0 and 1. When individual intervals
are requested, BONFER and SCHEFFE have no effect.
JOINT(a). Joint confidence intervals. Specify the desired confidence level in parentheses after the keyword. The default is 0.95. The desired confidence level can be any decimal number between 0 and 1.
UNIVARIATE(type). Univariate
confidence interval. Specify either SCHEFFE (for Scheffé intervals) or BONFER (for Bonferroni intervals) in parentheses
after the keyword. The default specification is SCHEFFE.