Here is one approach: library(MASS)
cor1 <- diag(2) cor1[1,2] <- cor1[2,1] <- 0.5 cor2 <- cor1 cor2[1,2] <- cor2[2,1] <- 0.9 sd <- c(5,20) mns <- c(50, 100) cov1 <- diag(sd) %*% cor1 %*% diag(sd) cov2 <- diag(sd) %*% cor2 %*% diag(sd) one <- mvrnorm(100, mns, cov1, empirical=TRUE) two <- mvrnorm(100, mns, cov2, empirical=TRUE) cor(one) cor(two) apply(one,2,mean) apply(two,2,mean) apply(one,2,sd) apply(two,2,sd) plot(one, col='blue') points(two, col='green') abline( lm(one[,2] ~ one[,1]), col='blue' ) abline( lm(two[,2] ~ two[,1]), col='green' ) You can modify values to fit your situation better. Hope this helps, -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of syrvn > Sent: Friday, January 29, 2010 8:09 AM > To: r-help@r-project.org > Subject: [R] Vectors with equal sd but different slope > > > Hi, > > what I would need are 2 vector pairs (x,y) and (x1,y1). x and x1 must > have > the same sd. y and y1 should also exhibit the same sd's but different > ones > as x and x1. Plotting x,y and x1,y1 should produce a plot with 2 > vectors > having a different slope. Plotting both vector pairs in one plot with > fixed > axes should reveal the different slope. > > > many thanks > syrvn > -- > View this message in context: http://n4.nabble.com/Vectors-with-equal- > sd-but-different-slope-tp1415562p1415562.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. ______________________________________________ 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.
