Mike Williamson
2008-Dec-18 23:17 UTC
[R] How to make a smooth ( linear ) CDF plot? -- Thanks!
All, Thanks for all of your help & advice! I created a plot starting with qqnorm, if I remember right, but I had to add a LOT of extras. I was surprised that it doesn't include the probability (e.g. 50% at mean) and instead provides the standard deviations (e.g., 0 at mean) on the axis. Plus, there is no line through Q1 & Q3 to help give a sense of the normality of the graph. I added these things & was in the end happy with the code, but it was surprisingly not trivial. The qqnorm & qqplot, as given, are not too useful for any practical engineering analysis. I am not yet savvy enough with 'R' to create a package, but if anyone out there is curious, let me know & I can supply the code. Thanks! Mike On Thu, Dec 18, 2008 at 4:21 AM, Mike Lawrence <mike@thatmike.com> wrote:> On Mon, Dec 15, 2008 at 9:48 PM, Mike Williamson <this.is.mvw@gmail.com>wrote: > >> I want to make some simple CDF (cumulative distribution function) plots >> to check whether distributions are Gaussian / normal. > > > qqnorm() > > >> As long as I am asking: I also want to plot more than one distribution >> or group. For instance, I want to plot 3 different factors on the same >> graph, where each factor has it's own cdf line. Any ideas for this? > > > a=qqnorm(rnorm(100)) > b=qqnorm(runif(100)) > > plot( > a$x[order(a$x)] > ,a$y[order(a$x)] > ,type='l' > ,ylim=c(min(c(a$y,b$y)),max(c(a$y,b$y))) > ,xlim=c(min(c(a$x,b$x)),max(c(a$x,b$x))) > ) > lines( > b$x[order(b$x)] > ,b$y[order(b$x)] > ,col='red' > ) > > -- > Mike Lawrence > Graduate Student > Department of Psychology > Dalhousie University > www.thatmike.com > > Looking to arrange a meeting? Do so at: > http://www.timetomeet.info/with/mike/ > > ~ Certainty is folly... I think. ~ >-- The official inflation rate in Zimbabwe has soared to about 231 million percent while thousands of Zimbabweans stand in line for their daily allowance of about 2 cents a day -- from their own bank accounts. The allowance does not afford them a half loaf of bread. [[alternative HTML version deleted]]