[R] please help! what are the different using log-link function and log transformation?

I'm new R-programming user, I need to use gam function. y-gam(a~s(b),family=gaussian(link=log),data) y-gam(loga~s(b), family =gaussian (link=identity),data) why these two command results are different? I guess these two command results are same, but actally these two command results are

Re: [R] please help! what are the different using log-link function and log transformation?

- Rubén H. Roa-Ureta, Ph. D. AZTI Tecnalia, Txatxarramendi Ugartea z/g, Sukarrieta, Bizkaia, SPAIN -Original Message- From: r-help-boun...@r-project.org on behalf of pigpigmeow Sent: Sun 6/19/2011 9:39 AM To: r-help@r-project.org Subject: [R] please help! what are the different using

Re: [R] please help! what are the different using log-link function and log transformation?

are the different using log-link function and log transformation? I'm new R-programming user, I need to use gam function. y - gam(a ~ s(b), family = gaussian(link=log), data) y - gam(log(a) ~ s(b), family = gaussian (link=identity), data) why [do] these two command [give different] results? I guess

Re: [R] please help! what are the different using log-link function and log transformation?

...@csiro.au Sent: Sun 6/19/2011 2:36 PM To: gloryk...@hotmail.com; r-help@r-project.org Subject: Re: [R] please help! what are the different using log-link function and log transformation? The two commands you give below are certain to lead to very different results, because they are fitting very