[R] regression for several responses

[Spencer Graves]

Consider the following:

 > tstdat <- data.frame(x=1:8, y1=rep(1:4, each=2), y2=0.01*rnorm(8))
 >
 > ys <- names(tstdat)[2:3]
 >
 > slopes <- rep(NA,2)
 > names(slopes) <- ys
 >
 > for(i in 1:2){
+  mdl <- formula(paste(ys[i], "~ x"))
+  slopes[i] <- coef(lm(mdl, tstdat))[2]
+ }
 > slopes
           y1           y2
0.4761904762 0.0006521472

Is this what you want?

This could also be done with sapply.

hth.  spencer graves

Martin Wegmann wrote:
> hello, 
> 
> I only want to get the slope of a linear regression of ca. 100 variables 
> against time. 
> 
> I can do for each response (100 times)
> var1.lm <- lm(response~predictor)
> 
> but I thought that there might be an easier way of doing this. If I am 
> including more variables it is doing a multiple regression and the output 
> (slope) differs. 
>  
> any idea?
> 
> thanks Martin
> 
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