Rainer M Krug <[EMAIL PROTECTED]> wrote in news:[EMAIL PROTECTED]:
> Hi > > I have some density estimates obtained from density(). I would like > to calculate the sum of squares of these. As the x values of the > estimates are not the same, and I would prefer not to restrict the > estiomate to a certain range of x values, how can I do the > calculation? > > Lets say: > > d1 <- density(Data1) > d2 <- density(Data2) > > If the x values would be the same, I would: > > ssq <- sum( (d1$y - d2$y)^2 ) > > but as it isn't, I can't do that. > > is there an easy way to get the sum of squares? Presumably there is a common domain for these densities. Consider forcing the x values to be the same by identically specifying n=, from=, and to=? > ?density > x <- rnorm(200,1,1) > x2 <- rnorm(200,1,1) > d1 <- density(x, n=512, from=-1, to= 4) > d2 <- density(x2, n=512, from=-1, to= 4) > ssq <- sum( (d1$y - d2$y)^2 ) > ssq [1] 0.4722924 > x <- rnorm(200,1,1) > x2 <- rnorm(200,1.5,1) > d1 <- density(x, n=512, from=-1, to= 4) > d2 <- density(x2, n=512, from=-1, to= 4) > ssq <- sum( (d1$y - d2$y)^2 ) > ssq [1] 2.111498 -- David Winsemius ______________________________________________ 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.
