ESTIMATE Statement
- ESTIMATE 'label' < fixed-effect values ...>
< | random-effect values ...> , ...< /
options > ;
The ESTIMATE statement is exactly like a CONTRAST statement, except
only one-row L matrices are permitted. The actual estimate,
, is displayed along with its approximate
standard error. An approximate t-test that = 0 is also produced.
PROC MIXED selects the degrees of freedom to match those displayed
in the "Tests of Fixed Effects" table for the final effect
you list in the ESTIMATE statement. You can modify the degrees of
freedom using the DF= option.
If PROC MIXED finds the fixed-effects portion of the specified
estimate to be nonestimable, then it displays "Non-est" for the
estimate entries.
The following examples of ESTIMATE statements compute the mean of
the first level of A in the split-plot example
(see Example 41.1) for various inference spaces.
estimate 'A1 mean narrow' intercept 1
A 1 B .5 .5 A*B .5 .5 |
block .25 .25 .25 .25
A*Block .25 .25 .25 .25
0 0 0 0
0 0 0 0;
estimate 'A1 mean intermed' intercept 1
A 1 B .5 .5 A*B .5 .5 |
Block .25 .25 .25 .25;
estimate 'A1 mean broad' intercept 1
A 1 B .5 .5 A*B .5 .5;
The construction of the L vector for an ESTIMATE statement
follows the same rules as listed under the
CONTRAST statement.
You can specify the following options in the ESTIMATE statement
after a slash (/).
- ALPHA=number
-
requests that a t-type confidence interval be constructed
with confidence level 1-number.
The value of number must be between 0 and 1; the default is 0.05.
- CL
-
requests that t-type confidence limits be constructed. The
confidence level is 0.95 by default; this can be changed with the
ALPHA= option.
- DF=number
-
specifies the degrees of freedom for the t-test and confidence
limits. The default is the denominator degrees of freedom taken
from the "Tests of Fixed Effects" table and corresponds to the
final effect you list in the ESTIMATE statement.
- DIVISOR=number
-
specifies a value by which to divide all coefficients so that fractional
coefficients can be entered as integer numerators.
- E
-
requests that the L matrix coefficients be displayed. For
ODS purposes, the label of this "L Matrix Coefficients"
table is "Coefficients".
- GROUP coeffs
- GRP coeffs
-
sets up random-effect contrasts between different groups
when a GROUP= variable appears in
the RANDOM statement. By default, ESTIMATE statement
coefficients on random effects are distributed equally
across groups.
- LOWER
- LOWERTAILED
-
requests that the p-value for the t-test be based
only on values less than the t-statistic. A two-tailed
test is the default. A lower-tailed confidence limit is also
produced if you specify the CL option.
- SINGULAR=number
-
tunes the estimability checking as documented for the
CONTRAST statement.
- SUBJECT coeffs
- SUB coeffs
-
sets up random-effect contrasts between different subjects
when a SUBJECT= variable appears
in the RANDOM statement. By default, ESTIMATE statement
coefficients on random effects are distributed equally
across subjects.
For example, the ESTIMATE statement in the following
code from Example 41.5
constructs the difference
between the random slopes of the first two batches.
proc mixed data=rc;
class batch;
model y = month / s;
random int month / type=un sub=batch s;
estimate 'slope b1 - slope b2' | month 1 / subject 1 -1;
run;
- UPPER
- UPPERTAILED
-
requests that the p-value for the t-test be based only on
values greater than the t-statistic. A two-tailed test is the
default. An upper-tailed confidence limit is also produced if you
specify the CL option.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.