Hi Mick,
regarding your first question try the following,
#if `x' is your data vector, then y <- seq(min(x), max(x), length=200) hist(x, prob=TRUE) lines(y, dnorm(y, mean(x), sd(x)))
regarding your second question, you'd probably want to fit a mixture model -> look at package `mclust'.
help(package="mclust")
I hope it helps.
Best, Dimitris
---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven
Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/16/396887 Fax: +32/16/337015 Web: http://www.med.kuleuven.ac.be/biostat/ http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm
----- Original Message ----- From: "michael watson (IAH-C)" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, October 04, 2004 12:04 PM
Subject: [R] Help with normal distributions
Hi
I have two questions, the first perhaps dumber than the second.
Firstly, I have a data set, and when I plot a histogram it looks like a
normal distribution. So I want to overlay a bell-shaped normal
distribution on top of it, to demonstrate how similar it is to the
normal distribution. I have read the help on dnorm(), rnorm(), pnorm()
etc but still can't figure out how to plot a normal distribution. Any
code would be appreciated....
Secondly, and perhaps more difficult, is a second data set. This, when
plotted as a histogram, has two clear peaks, perhaps even three, all of
which look as though they are normally distributed. So the theory is
that my data set is actually made up of two, possibly three, underlying
sub-sets of data which are normally distributed, but with different
means and standard deviations. So 1) how do I test for this? And 2) how
can I estimate the parameters (mean and SD) for the underlying
distributions?
Thanks in advance for your help
Mick
______________________________________________
[EMAIL PROTECTED] mailing list
https://stat.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://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
