I'm beginner in R! I have a lot of problems on R..... I have three questions about GAM 1. What is the function of Gaussian distribution in GAM?(if I choose family is Gaussian) Is it used in the predictand value (Y)? 2. How to plot a graph the gam function? For example: y<-gam(a~s(b),family=gaussian (link=log) ,Data) how to plot x axis is s(b) and y axis is log a??? 3. if I use GAM to create an equation with smoothing function For example: y<-gam(a~s(b)+s(c),family=gaussian (link=log),Data) how to get the coefficient of s(b) , s(c) My final target is getting the GAM equation to predict a, so I need to know how to get the coefficient of equation and how to write the equation!!! As I know, I'm silly to ask these questions. But GAM is very difficult to me. From now on, I need to clear the concept of GAM. Thank YOU! -- View this message in context: http://r.789695.n4.nabble.com/About-GAM-in-R-Need-YOUR-HELP-tp3610522p3610522.html Sent from the R help mailing list archive at Nabble.com.
On Jun 20, 2011, at 1:25 AM, pigpigmeow wrote:> I'm beginner in R! I have a lot of problems on R..... > > I have three questions about GAM > 1. What is the function of Gaussian distribution in GAM?(if I choose > family > is Gaussian)Specifies an an error distribution.> Is it used in the predictand value (Y)?I don't understand the question except to say that model structure would always influence predictions.> > 2. How to plot a graph the gam function? > For example: y<-gam(a~s(b),family=gaussian (link=log) > ,Data) > how to plot x axis is s(b) and y axis is log a???The usual way to plot an R regression object is to plot the predicted values against the inputs. You should be looking for the "predict" functions in whatever (unstated) package you are using.> > 3. if I use GAM to create an equation with smoothing function > For example: y<-gam(a~s(b)+s(c),family=gaussian (link=log),Data) > how to get the coefficient of s(b) , s(c)Again: ?predict You can also look at the fit object with str() but from your other questions and apparent difficulties, I am guessing that may be "too much information".> My final target is getting the GAM equation to predict a, so I need > to know > how to get the coefficient of equation and how to write the > equation!!!Spline fits will generally be complex curves and graphical output is usually the way to evaluate and display the results. There will not be a single coefficient that you can point to and say "that" is the effect.> > > As I know, I'm silly to ask these questions. But GAM is very > difficult to > me. From now on, I need to clear the concept of GAM.Get a good book and read more.> > Thank YOU! > > > -- > View this message in context: http://r.789695.n4.nabble.com/About-GAM-in-R-Need-YOUR-HELP-tp3610522p3610522.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.David Winsemius, MD West Hartford, CT
If you use the mgcv package for GAMs, I found this book very helpful: Wood, SN Generalized additive models: An introduction with R CRC Press, 2006 ISBN-13: 9781584884743 --Chris Ryan SUNY Upstate Medical University On Mon, Jun 20, 2011 at 1:25 AM, pigpigmeow <glorykwok at hotmail.com> wrote:> I'm beginner in R! I have a lot of problems on R..... > > I have three questions about GAM > 1. What is the function of Gaussian distribution in GAM?(if I choose family > is Gaussian) > Is it used in the predictand value (Y)? > > 2. How to plot a graph the gam function? > For example: y<-gam(a~s(b),family=gaussian (link=log) > ,Data) > how to plot x axis is s(b) and y axis is log a??? > > > 3. if I use GAM to create an equation with smoothing function > For example: y<-gam(a~s(b)+s(c),family=gaussian (link=log),Data) > how to get the coefficient of s(b) , s(c) > My final target is getting the GAM equation to predict a, so I need to know > how to get the coefficient of equation and how to write the equation!!! > > > As I know, I'm silly to ask these questions. But GAM is very difficult to > me. From now on, I need to clear the concept of GAM. > > Thank YOU! > > > -- > View this message in context: http://r.789695.n4.nabble.com/About-GAM-in-R-Need-YOUR-HELP-tp3610522p3610522.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. >
Actually, I 'm using "mgcv" package. But I learnt basic linear regression in my school, it is really hard for me to handle these problem! by the way, i need to work harder! -- View this message in context: http://r.789695.n4.nabble.com/About-GAM-in-R-Need-YOUR-HELP-tp3610522p3611796.html Sent from the R help mailing list archive at Nabble.com.