Hi All, I would like to run a linear model where the response is the duration of relief in days and the regressor is the drug dosage in mg. Then I would like compute the predicted values of the duration of relief from the model and merge it into the original data. I am not sure how the merge happens since if I have missing values in the data, R runs the resgression model but fitted values for some observations are not being calculated. Below is my R script Mydata<-read.csv(file=?file1.csv?, header=T) Model<-lm(y ~ x, data=Mydata) f<-fitted(Model) Newdata<-cbind(f , Mydata) Is Newdata merged correctly? Thanks for your help -- View this message in context: http://www.nabble.com/how-to-merge-the-fitted-values-from-a-linear-model--tp25248552p25248552.html Sent from the R help mailing list archive at Nabble.com.
Chuck Cleland
2009-Sep-02 00:13 UTC
[R] how to merge the fitted values from a linear model?
On 9/1/2009 6:32 PM, kayj wrote:> Hi All, > > I would like to run a linear model where the response is the duration of > relief in days and the regressor is the drug dosage in mg. Then I would like > compute the predicted values of the duration of relief from the model and > merge it into the original data. I am not sure how the merge happens since > if I have missing values in the data, R runs the resgression model but > fitted values for some observations are not being calculated. > > Below is my R script > > Mydata<-read.csv(file=?file1.csv?, header=T) > > Model<-lm(y ~ x, data=Mydata) > f<-fitted(Model) > Newdata<-cbind(f , Mydata) > > Is Newdata merged correctly? > > Thanks for your helpYou might try something like this: DF <- data.frame(Y = rnorm(20), X = sample(c(NA,0,1,2,3), size=20, replace=TRUE)) DF$f <- fitted(lm(Y ~ X, data=DF, na.action=na.exclude)) DF Y X f 1 0.81371693 2 0.1116813 2 -0.36585221 0 -0.8160565 3 -1.07271855 0 -0.8160565 4 1.27182331 1 -0.3521876 5 -0.12492961 2 0.1116813 6 -1.84241736 0 -0.8160565 7 -0.28532869 1 -0.3521876 8 1.17361614 NA NA 9 0.88190221 3 0.5755502 10 0.92742858 1 -0.3521876 11 -1.18675102 0 -0.8160565 12 0.38076816 NA NA 13 -1.31518961 0 -0.8160565 14 -1.07973072 1 -0.3521876 15 0.00431749 3 0.5755502 16 0.49820163 3 0.5755502 17 -0.21377954 1 -0.3521876 18 -1.03107537 2 0.1116813 19 -1.23459162 0 -0.8160565 20 -0.05666561 0 -0.8160565 -- Chuck Cleland, Ph.D. NDRI, Inc. (www.ndri.org) 71 West 23rd Street, 8th floor New York, NY 10010 tel: (212) 845-4495 (Tu, Th) tel: (732) 512-0171 (M, W, F) fax: (917) 438-0894