You can also do the regressions "in parallel" as follows:

x = -25:25
y = 0.05*x^2  + 2* x - 4
y1 = y + rcauchy(51)
y2 = y + rcauchy(51)^2
y3 = y/10 - 5 + rnorm(51)

Y = cbind(y, y1, y2, y3)

m = lm(Y~x)
print(coef(m))

Hope this helps,

Michael

On Fri, Sep 16, 2011 at 3:37 PM, Luke Miller <millerlp@gmail.com> wrote:

> Create an output vector to hold your slopes before starting the loop, then
> use your index i to place each new slope in the appropriate position in
> your
> vector.
>
> y1<-rnorm(100, mean=0.01, sd=0.001)
> y2<-rnorm(100, mean=0.1, sd=0.01)
>
> x<-(c(10,400))
>
> my.slopes = vector("numeric",100)  #  initialize a numeric vector, length
> 100, filled with zeros initially
>
> for (i in 1:100) {
>
> #create the linear model for each data set
> model1<-lm(c(y1[i],y2[i])~x)
> slope1<-model1$coefficients[2]
> my.slopes[i] = slope1 #  stick each new slope value into my.slopes[i]
> }
>
> You could skip the slope1 <- model1$coefficients[2]  step and just put the
> slope directly into my.slopes[i] as well.
>
> On Fri, Sep 16, 2011 at 3:25 PM, <Beaulieu.Jake@epamail.epa.gov> wrote:
>
> > Hello,
> >
> > I would like to write a loop to 1) run 100 linear regressions, and 2)
> > compile the slopes of all regression into one vector.  Sample input data
> > are:
> >
> > y1<-rnorm(100, mean=0.01, sd=0.001)
> > y2<-rnorm(100, mean=0.1, sd=0.01)
> >
> > x<-(c(10,400))
> >
> > #I have gotten this far with the loop
> >
> > for (i in 1:100) {
> >
> > #create the linear model for each data set
> > model1<-lm(c(y1[i],y2[i])~x)
> > slope1<-model1$coefficients[2]
> > }
> >
> > How can I compile the slopes from all 100 regressions into one vector?
> >
> > Thanks,
> > Jake
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > 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.
> >
>
>
>
> --
> ___________________________
> Luke Miller
> Postdoctoral Researcher
> Marine Science Center
> Northeastern University
> Nahant, MA
> (781) 581-7370 x318
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>

	[[alternative HTML version deleted]]

