+--------------------------------------------------------------------+
| |
| STANDARD ERROR OF ESTIMATE |
| |
+--------------------------------------------------------------------+
MEANING: NONMEM's estimate of the precision of its parameter estimates
CONTEXT: NONMEM output
DISCUSSION:
Asymptotic statistical theory applied to extended least-squares esti-
mation (as used in NONMEM) says that the distribution of the parameter
estimators is multivariate normal, with variance-covariance matrix
that can be estimated from the data. NONMEM supplies such an estimate
(See covariance matrix of estimate). The square root of the ith diag-
onal element of the matrix is the standard error of the ith parameter
estimate. NONMEM output presents standard errors as in this example.
****** STANDARD ERROR OF ESTIMATE ********************
THETA - VECTOR OF FIXED EFFECTS PARAMETERS **********
TH 1 TH 2
6.27E+00 1.92E+01
OMEGA - COV MATRIX FOR RANDOM EFFECTS - ETAS ********
ETA1 ETA2
ETA1 1.71E-02
ETA2 ......... 1.12E-01
SIGMA - COV MATRIX FOR RANDOM EFFECTS - EPSILONS ****
EPS1
EPS1 5.57E-03
Note that standard errors are given for all types of population param-
eters: THETA, the vector of fixed effects parameters, and OMEGA and
SIGMA, the matrices of random effects parameters. In this example,
the 2x2 matrix, OMEGA, was constrained to be diagonal; the omitted
entry (.........) indicates that the element omega(2,1) is not esti-
mated, and consequently has no standard error.
REFERENCES: Guide I Section C.3.5.2
REFERENCES: Guide V Section 5.4.2.1
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