On 26-Sep-05 nwew wrote: > Dear R-users, > > I have the following data > > x <- runif(300,min=1,max=230) > > y <- x*0.005 + 0.2 > y <- y+rnorm(100,mean=0,sd=0.1) > y <- y%%1 # <------- modulo operation > plot(x,y) > > and would like to recapture the slope (0.005) and intercept(0.2). > I wonder if there are any clever algorithms to do this. I was > looking at the function lm.cirucalar. Is this the method to use? > If, which of the references is best too look at? > > Eryk
Hi Eryk, If you know the modulus (in your case 1.0) and you get data that look like the result of your "plot(x,y)", then I wouldn't mess about. I would simply do something like y1<-y ix <- ix<-(y < 0.9*(x-50)/200) y1[ix] <- y1[ix]+1.0 lm(y1~x) (the constants 0.9/200, -50 being chosen to give a good separation on the graph). On the other hand, if there are good reasons why this very simple approach is not suitable, then if we knew what they were a more helpful reply would be easier to formulate! Best wishes, Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <[EMAIL PROTECTED]> Fax-to-email: +44 (0)870 094 0861 Date: 26-Sep-05 Time: 15:56:48 ------------------------------ XFMail ------------------------------ ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
