Dear Petr, Probably I don't understand exactly what you are looking for. However your "plot(x,c(y,z))" suggests a broken-line model for the response "c(y,x)" versus the variables x. Therefore you could estimate a segmented model to obtain (different) slope (and breakpoint) estimates. See the package segmented.
best, vito ----- Original Message ----- From: Petr Pikal <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, June 15, 2004 1:11 PM Subject: [R] slope estimations of teeth like data > Dear all > > Suppose I have teeth like data similar like > > x <- 1:200 > y <- 0.03*x[1:100]+rnorm(100, mean=.001, sd=.03) > z <- 3-rep(seq(1,100,10),each=10)*.03+rnorm(100,mean=.001, sd=.03) > plot(x,c(y,z)) > > and I want to have a gradient estimations for some values from increasing part of > data > > like > > y.agg <- aggregate(diff(c(y,z)), list(rep(seq(1,200,10),each=10)[1:199]), mean) > > y.agg[1:10,] ##is OK, I want that > y.agg[11:20,] ##is not OK, I do not want that > > actual data are similar but more irregular and have subsequent gradual increases > and decreases, more like > > set.seed(1) > yy<-NULL > for( i in 1:10) yy <- c(yy,c(y,z)[1:floor(runif(1)*200)]) > length(yy) > [1] 1098 > > plot(1:1098,yy) > > Is there anybody who has some experience with such data, mainly how to extract > only increasing portions or to filter values of "yy" such as only aggregated slopes > from increasing parts are computed and other parts are set to NA. Sometimes > actual data have so long parts of steady or even slightly increasing values at > decreasing part that aggregated values are slightly positive although they are > actually from decreasing portion of data. > > Thank you > Petr Pikal > [EMAIL PROTECTED] > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html