[R] Help needed: Fraction for Histogram > 1 ???

[charles78]

It is not the case as you described.  In any case, the total area should be 1
and labeled fraction on y axis should be far less than 1, since I have more
than 10000 data points.  I also test differerent bin size by change the
break.

I draw the graph using only 1 group, the same result was obtained.

Any othe suggestion?

Charles.  

Greg Snow-2 wrote:
> 
> When freq=FALSE then the y axis is not the proportion in each group (what
> I am assuming you mean by fraction), but rather is scaled so that the
> total area of the histogram is 1 (making comparing to theoretical
> densities easier).  If all the data values are between 0 and 1, then the
> height of at least one bar needs to be >= 1 for the total area to equal 1.
> 
> If you want the y-axis to show relative frequency (proportion, fraction,
> etc.), then you either need to plot the y-axis yourself or use a different
> function than 'hist'.
> 
> -- 
> Gregory (Greg) L. Snow Ph.D.
> Statistical Data Center
> Intermountain Healthcare
> greg.snow at imail.org
> 801.408.8111
> 
> 
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of charles78
>> Sent: Monday, June 22, 2009 10:08 AM
>> To: r-help at r-project.org
>> Subject: [R] Help needed: Fraction for Histogram > 1 ???
>> 
>> 
>> I have been trying to draw histogram for my manscript and found some
>> strange
>> things that I could not figure out why.
>> 
>> Using the same code listed below I have successfully draw histograms
>> for a
>> few figures with fraction labeled on Y axis less than 1 (acturally
>> between 0
>> to 0.1).  But one dataset gives the Y axis label 0 to 5 as fraction.
>> This
>> is not true, as fraction are less than 1, although the value
>> distribution on
>> the figure seems to me is right.
>> 
>> The only difference between the first few datasets and last dataset is:
>> 
>> All values for the first few data sets > 1.
>> 
>> The values for the last data sets between 0 and <1.
>> 
>> Any idea why this happens.
>> 
>> Your help is highly appreciated.
>> 
>> Charles
>> 
>> ===================================================
>> postscript("Figure.eps", paper="letter", horizontal=FALSE)
>> par(mfrow=c(3,3))
>> par(omi=c(2,0.2,1.8,0.2), mai=c(0.4, 0.4, 0.5, 0.1) )
>> 
>> my.input <- read.table("input.data", header=FALSE, sep="\t")
>> my.input.exp <- read.table("exp.data", header=FALSE, sep="\t")
>> 
>> hist(my.input.exp[,2], breaks=40,freq = FALSE,xlab="", border =
>> "grey30",
>> ylab="", main="")
>> hist(my.input[,2], breaks=40,freq = FALSE,xlab="", ylab="", main="",
>> border
>> = "red",add =TRUE)
>> mtext("Fraction", side=2, line=2, cex=0.7)
>> box()
>> ======================================================
>> --
>> View this message in context: http://www.nabble.com/Help-needed%3A-
>> Fraction-for-Histogram-%3E-1-----tp24150345p24150345.html
>> Sent from the R help mailing list archive at Nabble.com.
>> 
>> ______________________________________________
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>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
> 
> ______________________________________________
> 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.
> 
> 

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