[R] subset factor?

[Peter Ehlers]

On 2011-01-14 06:20, Sarah Goslee wrote:
> Are you certain they are numeric? Have you tried
> str() on your data?
>
> Sarah
>

Silvano:

As Sarah says, do str(dados) to see that 'doses' is
NOT numeric. The error message is very clear; it tells you
that 'doses' is a factor. My guess is that you imported
your data from somewhere and somehow managed to import
'doses' as a factor. My advice is to ALWAYS do an str()
after importing/changing data.

Peter Ehlers

> On Fri, Jan 14, 2011 at 9:08 AM, Silvano<silvano at uel.br>  wrote:
>> Hi,
>>
>> I used subset command, like this:
>>
>> grupoP = subset(dados, grupos=='P',  select=c(mortos, vivos, doses,
>> percevejos, p))
>>
>> and the variables in select option are numeric.
>>
>> I tried fit a model with command:
>>
>> ajuste.logit = glm(cbind(mortos,percevejos)~log10(doses),
>> family=binomial(logit), data=grupoP)
>>
>> and the output is:
>>
>>> ajuste.logit = glm(cbind(mortos,percevejos)~log10(doses),
>>> family=binomial(logit), data=grupoP)
>>
>> Erro em Math.factor(doses) : log10 not meaningful for factors
>>
>> what is wrong with my commands? Why doses aren't numeric?
>>
>> Thanks,
>>
>
>
>