bigglm binomial negative fitted value

[pipehappy]

Hi, there

Since glm cannot handle factors very well. I try to use bigglm like this:

logit_model <- bigglm(responser~var1+var2+var3, data, chunksize=1000,
family=binomial(), weights=~trial, sandwich=FALSE)

fitted <- predict(logit_model, data)

only var2 is factor, var1 and var3 are numeric.

I expect fitted should be a vector of value falls in (0,1)

However, I get something like this:
str(fitted)
 num [1:260617, 1] -0.0564 -0.0564 -0.1817 -0.1842 -0.1852 ...
 - attr(*, "dimnames")=List of 2
  ..$ : chr [1:260617] "1" "2" "3" "4" ...
  ..$ : NULL

Anyone can help on this case? Thank you in advance.

Best,

--Yue

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[Thomas Lumley-2]

On Fri, Jun 1, 2012 at 1:17 AM, Yue Guan <[hidden email]> wrote:

> Hi, there
>
> Since glm cannot handle factors very well. I try to use bigglm like this:
>
> logit_model <- bigglm(responser~var1+var2+var3, data, chunksize=1000,
> family=binomial(), weights=~trial, sandwich=FALSE)
>
> fitted <- predict(logit_model, data)
>
> only var2 is factor, var1 and var3 are numeric.
>
> I expect fitted should be a vector of value falls in (0,1)
>
> However, I get something like this:
> str(fitted)
>  num [1:260617, 1] -0.0564 -0.0564 -0.1817 -0.1842 -0.1852 ...
>  - attr(*, "dimnames")=List of 2
>  ..$ : chr [1:260617] "1" "2" "3" "4" ...
>  ..$ : NULL
>

As the help says, the default is predictions of the linear predictor.
To get predictions of the probability, use type="response"

   -thomas

--
Thomas Lumley
Professor of Biostatistics
University of Auckland

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[pipehappy]

Thank you very much. I do overlook something.....

On Thu, May 31, 2012 at 5:20 PM, Thomas Lumley <[hidden email]> wrote:

> On Fri, Jun 1, 2012 at 1:17 AM, Yue Guan <[hidden email]> wrote:
>> Hi, there
>>
>> Since glm cannot handle factors very well. I try to use bigglm like this:
>>
>> logit_model <- bigglm(responser~var1+var2+var3, data, chunksize=1000,
>> family=binomial(), weights=~trial, sandwich=FALSE)
>>
>> fitted <- predict(logit_model, data)
>>
>> only var2 is factor, var1 and var3 are numeric.
>>
>> I expect fitted should be a vector of value falls in (0,1)
>>
>> However, I get something like this:
>> str(fitted)
>>  num [1:260617, 1] -0.0564 -0.0564 -0.1817 -0.1842 -0.1852 ...
>>  - attr(*, "dimnames")=List of 2
>>  ..$ : chr [1:260617] "1" "2" "3" "4" ...
>>  ..$ : NULL
>>
>
> As the help says, the default is predictions of the linear predictor.
> To get predictions of the probability, use type="response"
>
>   -thomas
>
> --
> Thomas Lumley
> Professor of Biostatistics
> University of Auckland

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.