Thanks alot for the quick responses. I have some additional questions related to this topic. In fact, my intention was to be able to answer questions like what percent of the regressions have p_values less than a certain threshold, how do residuals look like, how do the plots of y vs. x look like, etc. I tried the following commands and found that the second line (and similar ones) does not work for extracting certain statistics.
regress=lapply(split(egfr, as.factor(egfr$P_ID)), function(df) {anova(lm(VALUE ~ LAB_DT, data=df)) }) regress[1]$residuals; regress[1]$fstatistic[1] So, is it possible to record statistics of each regression such as p_value, F-value, residuals, etc. as a vector? Thanks, On Dec 28, 6:23 pm, Entropi ntrp <entropy...@gmail.com> wrote: > Hi, > I have been examining large data and need to do simple linear regression > with the data which is grouped based on the values of a particular > attribute. For instance, consider three columns : ID, x, y, and I need to > regress x on y for each distinct value of ID. Specifically, for the set of > data corresponding to each of the 4 values of ID (76,111,121,168) in the > below data, I should invoke linear regression 4 times. The challenge is > that, the length of the ID vector is around 20000 and therefore linear > regression must be done automatically for each distinct value of ID. > > ID x y > 76 36476 15.8 76 36493 66.9 76 36579 65.6 111 35465 10.3 111 35756 4.8 > 121 38183 16 121 38184 15 121 38254 9.6 121 38255 7 168 37727 21.9 168 > 37739 29.7 168 37746 97.4 > I was wondering whether there is an easy way to group data based on the > values of ID in R so that linear regression can be done easily for each > group determined by each value of ID. Or, is the only way to construct > loops with 'for' or 'while' in which a matrix is generated for each > distinct value of ID that stores corresponding values of x and y by > screening the entire ID vector? > > Thanks in advance, > > Yasin > > [[alternative HTML version deleted]] > > ______________________________________________ > r-h...@r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.