R help - Mar 2012 - Why predicted values are fewer that the real?

Hi

i am running a glm model family Gamma(link=log) trying to predict a vector
of 1554 (real) values 

Using predict() i got a vector of 950 predicted values instead of 1554.
The predictions are good though
The model doesnt take account of negative values and NAs which are only 121
values.

Any clue?

Thank

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Hi,

On Fri, Mar 2, 2012 at 11:19 AM, labbig <lkaimaka at windowslive.com>
wrote:
> Hi
>
> i am running a glm model family Gamma(link=log) trying to predict a vector
> of 1554 (real) values
>
> Using predict() i got a vector of 950 predicted values instead of 1554.
> The predictions are good though
> The model doesnt take account of negative values and NAs which are only 121
> values.
>
> Any clue?
To have a clue, we need far more information than you've provided, possibly
even the reproducible example requested in the posting guide.
> Thank
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Why-predicted-values-are-fewer-that-the-real-tp4438912p4438912.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org 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.


-- 
Sarah Goslee
http://www.functionaldiversity.org

try using glm(...,na.action=na.exclude)

See ?na.exclude

for the explanation

On Fri, Mar 2, 2012 at 11:19 AM, labbig <lkaimaka@windowslive.com> wrote:
> Hi
>
> i am running a glm model family Gamma(link=log) trying to predict a vector
> of 1554 (real) values
>
> Using predict() i got a vector of 950 predicted values instead of 1554.
> The predictions are good though
> The model doesnt take account of negative values and NAs which are only 121
> values.
>
> Any clue?
>
> Thank
>
> --
> View this message in context:
>
http://r.789695.n4.nabble.com/Why-predicted-values-are-fewer-that-the-real-tp4438912p4438912.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
>
http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

On Mar 2, 2012, at 11:19 AM, labbig wrote:
> Hi
>
> i am running a glm model family Gamma(link=log) trying to predict a  
> vector
> of 1554 (real) values
>
> Using predict() i got a vector of 950 predicted values instead of  
> 1554.
> The predictions are good though
> The model doesnt take account of negative values and NAs which are  
> only 121
> values.
Taking the logs of negative numbers?
> Any clue?
I see a couple of possibilities.
> View this message in context:
http://r.789695.n4.nabble.com/Why-predicted-values-are-fewer-that-the-real-tp4438912p4438912.html
> Sent from the R help mailing list archive at Nabble.com.
-- 
David Winsemius, MD
West Hartford, CT