[R] multiple graphs on one plot

[Andrew Halford]

Hi Listers

I've been trying to make a single graphic that has frequency histograms for
male and female mud crabs displayed side by side (such as when using the
beside=TRUE command for barplots). I then want to display a normal
distribution on top of the male and female histograms.

I have been using the multhist command in Plotrix to generate the
histograms without too much problem, but I cannot get the normal
distributions to plot up on the same graph.

Histograms plot

mf <-
list(lf_crabs$cw[lf_crabs$sex=='female'],lf_crabs$cw[lf_crabs$sex=='male'])
multhist(mf, xlab="CW", ylab="Frequency", ylim=c(0,100),main="All Measured
Crabs", col=c("dark gray", "light gray"),
         breaks=seq(90,210, by=10),beside=TRUE,space=c(0,0.5))
legend("topright", c("Females", "Males"), fill=c("dark gray", "light gray"))

Then I try to add a normal distribution curve just to the female data but I
cant get the output to plot

points(seq(min(mf[[1]]), max(mf[[1]]), length.out=300),
       dnorm(seq(min(mf[[1]]), max(mf[[1]]), length.out=300),
             mean(mf[[1]]), sd(mf[[1]])),type="l", col="dark gray")

Even trying to add an abline to the plot doesn't work.

What am I missing?

cheers

Andy

-- 
Andrew Halford Ph.D
Senior Coastal Fisheries Scientist
Pacific Community | Communauté du Pacifique CPS – B.P. D5 | 98848 Noumea,
New Caledonia | Nouméa, Nouvelle-Calédonie

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