[R] Re : A question on histogram - area much less than 1
Pascal Oettli
kridox at ymail.com
Mon Mar 12 09:03:13 CET 2012
Hi Miao,
With option freq=FALSE, the function hist calculates densities, i.e. in your case,
counts/total/length in-between breaks.
h <- hist(Y1, breaks=seq(0, 350, by=35),freq=FALSE)
If you calculate:
h$counts/sum(h$counts)/35 = h$density
Regards,
Pascal
----- Mail original -----
De : jpm miao <miaojpm at gmail.com>
À : r-help at r-project.org
Cc :
Envoyé le : Lundi 12 mars 2012 16h42
Objet : [R] A question on histogram - area much less than 1
Hello,
I have problem running the histogram function "hist". The area under the
histogram is much lower than 1. Could anyone tell me what the problem is?
Thanks,
(The total number of observation is 992 (close to 1000), so the
probability that 0<Y1<35 is approximately 0.277)
miao
rm(list=ls())
par(mfrow=c(1, 1))
Y <- cbind(matrix(35*0.5,1,277), matrix(35*1.5, 1, 146), matrix(35*2.5, 1,
99), matrix(35*3.5,1,80), matrix(35*4.5, 1, 69), matrix(35*5.5, 1, 63),
matrix(35*6.5, 1, 52), matrix(35*7.5,1, 53), matrix(35*8.5, 1, 55),
matrix(35*9.5, 1, 98))
Y1<-as.vector(Y)
par(mar=c(4.5, 4.1, 3.1, 0))
hist(Y1, breaks=seq(0, 350, by=35), ylim=c(0, 0.3), col="grey80",
freq=FALSE)
par(mar=c(5.1, 4.1, 4.1, 2.1))
[[alternative HTML version deleted]]
______________________________________________
R-help at 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.
More information about the R-help
mailing list