Displaying 2 results from an estimated 2 matches for "zeta_k".
2004 Jan 08
3
Strange parametrization in polr
In Venables \& Ripley 3rd edition (p. 231) the proportional odds model
is described as:
logit(p<=k) = zeta_k + eta
but polr apparently thinks there is a minus in front of eta,
as is apprent below.
Is this a bug og a feature I have overlooked?
Here is the naked code for reproduction, below the results.
------------------------------------------------------------------------
---
version
library( MASS )...
2010 Sep 27
1
Ordered logit with polr won't match SPSS output
I am learning R via a textbook that performs analysis with SPSS and SAS. In
trying to reproduce the results for an ordinal logit model, I get very
similar point estimates for my cut-off points, but the parameters for the
covariate q60 do not match. The estimate for q51 also matches. Is this
because I need to change a base case for the ordered covariate q60? Can this
be done in or is it always the