[R] lm - log(variable) - skip log(0)

[David Winsemius]

On Feb 25, 2011, at 7:25 AM, agent dunham wrote:

>
> Apologies, I'm really new with R, Can you help me with the syntax?
>
> here is my data.frame in which I introduce independent variables:
>
>> varind <-
>> data.frame(datpos$hdom2,datpos$NumPies,datpos$InHart,datpos 
>> $CV,datpos$CA,datpos$FCC)
>
> varind has dimensions(194, 6), in case that's necessary. Then I type:
>
>> loglmp4 <- lm(log(datpos$IncAltuDom)~log(varind), subset=varind>0)

Because varind is now a dataframe, you need to refer to its columns  
when offering candidate independent variables to lm. It is not clear  
which column you wanted to test for positivity and  which use on the  
RHS from varind. You should also get in the habit of:

--- including context in followup questions
--- using the data= argument in model construction

Going back to your original question where the dataframe was named  
"dat"and it was clear what variable you wanted on the RHS:

lmod1.lm <- lm( log(inaltu)~log(indiam), data= dat, subset=(indiam > 0  
& inaltu > 0)  )

-- 
David.


>
> Error en model.frame.default(formula = log(datpos$IncAltuDom) ~  
> log(varind),
> :
>  invalid type (list) for variable 'log(varind)'
>
> Thanks again,user at host.com
> -- 
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>
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David Winsemius, MD
West Hartford, CT