I am not sure what you mean when you say it does not integrate to 1. Here are a couple of cases, and it seems fine to me:
> x <- density(1:30) > str(x) List of 7 $ x : num [1:512] -11.0 -10.9 -10.8 -10.7 -10.6 ... $ y : num [1:512] 6.66e-05 7.22e-05 7.84e-05 8.49e-05 9.20e-05 ... $ bw : num 4.01 $ n : int 30 $ call : language density.default(x = 1:30) $ data.name: chr "1:30" $ has.na : logi FALSE - attr(*, "class")= chr "density" > plot(x) > sum(diff(x$x) * (head(x$y,-1) + tail(x$y,-1))/2) # integrate [1] 1.000823 > x <- density(rnorm(1000)) > sum(diff(x$x) * (head(x$y,-1) + tail(x$y,-1))/2) # integrate [1] 1.000974 > On Nov 15, 2007 2:47 PM, Joren Heit <[EMAIL PROTECTED]> wrote: > Hello, > > I have a data set of about 300.000 measurements made by an STM which should > apporximately fix a normal (Gaussian) distribution. > I have imported the data in R and used plot(density()) to get a nice plot of > the distribution which in fact looks like a real Gaussian. > However, the integral over the surface is not equal to one (I know since > some of the plots extend to numbers greater then 1). Is there a way to > normalize the data so the density function will actualy yield the > probability of x (a height in my case)? > This is my code so far: > > #Input path > path <- "G:\\C\\Data txt\\1au300.txt" > > #Dataverwerking > data <- read.table(path, header=TRUE) > rows <- length(data$height) > height <- data$height[1:rows] > dens <-density(height) > > mean <- mean(height) > sd <- sd(height) > min <- min(hnorm) > max <- max(hnorm) > > #Plot > par(new=FALSE) > curve(dnorm(x,m=mean,sd=sd),from=min,to=max, xlab="", ylab="", col="white", > lwd=2) > points(dens, type="h", col="grey" ) > par(new=TRUE) > curve(dnorm(x,m=mean,sd=sd),from=min,to=max, xlab="Height (nm)", > ylab="Density", lwd=2, col="darkred") > > > Thanks > > [[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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve? ______________________________________________ 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.
