[R] Tobit variance covariance matrix

Leandro Magnusson Leandro_Magnusson at brown.edu
Tue Jul 11 08:27:44 CEST 2006


How can I recover the variance-covariance matrix of the tobit model from 
the variance-covariance of the survreg?
I first used to the survreg function and then I selected the variance 
matrix. However, the last parameter is log(scale) and not the variance 
of the standard deviation of the censored distribution as in the Tobit 
tobit<- survreg(Surv(y, y > 0, type ='left')~ 0+ z + vh, dist = 'gaussian');
Om   <- tobit$var;



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