Hello. I'm trying to use the function vif from package car in a lm. However
it returns the following error:
"Error in vif.default(lm(MDescores.sitescores ~ hidroperiodo + localizacao
+ : there are aliased coefficients in the model"
When I exclude any predictor from the model, it returns this warning
message:
"Warning message: In cov2cor(v) : diag(.) had 0 or NA entries; non-finite
result is doubtful"
When I exclude any other predictor from the model vif finally works. I
can't figure it out whats the problem. This are the results that R returns
me:
> vif(lm(MDescores.sitescores ~ hidroperiodo + localizacao + area +
profundidade + NTVM + NTVI + PCs...c.1.., data = MDVIF))
Error in vif.default(lm(MDescores.sitescores ~ hidroperiodo + localizacao +
: there are aliased coefficients in the model
> vif(lm(MDescores.sitescores ~ localizacao + area + profundidade + NTVM +
NTVI + PCs...c.1.., data = MDVIF))
GVIF Df GVIF^(1/(2*Df))
localizacao NaN 2 NaN
area NaN 1 NaN
profundidade NaN 1 NaN
NTVM NaN 1 NaN
NTVI NaN 1 NaN
PCs...c.1.. NaN 1 NaN
Warning message:
In cov2cor(v) : diag(.) had 0 or NA entries; non-finite result is doubtful
Thanks.
--
Rodolfo Mei Pelinson.
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