Displaying 2 results from an estimated 2 matches for "vcoc".
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vcc
2004 Jun 05
1
coef and vcoc for polr inconsistent??
Is the following an inconsistency, programming glitch or a feature?
One would expect that vcov(obj) was the variance-covariance of
coef(obj),
but apparently this is not the case for polr objects:
> x <- rnorm( 100 )
> y <- rnorm( 100 )
> ff <- factor( sample( 1:4, 100, replace=T ) )
> pm <- polr( ff ~ x + y )
> coef( pm )
x y
0.21219010 0.03558506
2008 Aug 06
1
Variance-covariance matrix for parameter estimates
Dear All,
I am currently working with the coxph function within the package survival.
I have the model h_ij = h_0(t) exp(b1x1 + b2x2) where the indicator
variables
are as follows:
x1 x2
VPS 0 0
LTG 1 0
TPM 0 1
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