multiple graphs on one plot

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 | Communaut? du Pacifique CPS ? B.P. D5 | 98848 Noumea,
New Caledonia | Noum?a, Nouvelle-Cal?donie

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Hi Andrew,
First, a little mind reading. My crystal ball says that "cw" can be
interpreted as "carapace width". It didn't tell me the parameters of
the distribution, so:

set.seed(1234)
mf<-list(rnorm(400,145,15),rnorm(400,160,15))
library(plotrix)
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"))
lines(seq(0,32,length.out=121),rescale(dnorm(90:210,145,15),c(0,100)))

This produces what I think you are after. Note that it may be
misleading as the distribution of carapace width in real mud crabs
doesn't look normal to me.

Jim

On Mon, May 13, 2019 at 3:00 PM Andrew Halford <andrew.halford at gmail.com>
wrote:

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 | Communaut? du Pacifique CPS ? B.P. D5 | 98848 Noumea,
New Caledonia | Noum?a, Nouvelle-Cal?donie

        [[alternative HTML version deleted]]