R baseplot :plotting 2 density plots in 1 plot cand hanging scales for x-Axis and y-Axis

Question

I have a question concerning plots in R using the baseplot-system: I want to plot 2 density plots in 1 plot. For this they need to have the same scales. I managed to change the scales so that I can plot them into 2 different plots. Thats exactly how I want them to look like:

 mexp = NULL
 for (i in 1 : 1000) mexp = c(mexp, mean(rexp(1000, 0.2)))
 hist(mexp, col="lightblue", main = "Averages of 40 exponentials")

plot(density(rnorm(1000,mean= 5)), bw=11,col="red" )
plot(   density( mexp , frequency(F)  ), col="green")  # frequency(F) adjusts the y-Axis

When I try to plot them into 1 plot it doesn`t work: I see the first plot only. I did this:

plot(density(rnorm(1000,mean= 5)), bw=11,col="red" )
line(   density( mexp , frequency(F) , col="green" )) 

Can anybody help me ? Thank you!

Answer 1

This code is better, but still contains several nonsense items.

First of all, it looks like you are comparing the wrong distributions. Your mexp data looks plausible. However, it looks like you are trying to compare it to a normal distribution with mean=5 and standard deviation=1. The mean is very close to the mean of your mexp data, but the mexp data has a mean of 0.157. You will not get much of a match like that.

Next the code has some mistakes and some absolute rubbish. Your first plot is:

plot(density(rnorm(1000,mean= 5)), bw=11,col="red" )

Aside from the fact that you have an inappropriate standard deviation for the normal distribution, you have bw=11 as an argument for plot, which no such argument. bw is an argument for density but this is probably not a good choice for bw on this data. Let's just plot it using the default choice of bw and adjust that later if needed. So a better version of your first curve would be:

plot(density(rnorm(1000,mean=5, sd=sd(mexp)), ),col="red" )

Next, you have

line(   density( mexp , frequency(F) , col="green" )) 

There is a function line, but that is not what you want here. You are looking for lines. With lines you are plotting another density. The argument col="green" is misplaced. You have it as an argument to density when it should be an argument for lines. And then there is frequency(F). This is gibberish. Here F will be treated as the logical value FALSE. frequency will consider that as a time series and find the frequency so that will give the value 1. You are then supplying that as the second argument of density so it will be treated as a bandwidth. This is total nonsense. Let's just delete it. That leaves us with lines(density(mexp), col="green") Putting this all together, we get:

plot(density(rnorm(1000,mean=5, sd=sd(mexp)), ),col="red" )
lines(density(mexp) , col="green" )

This may not be exactly what you need but will be a better starting point.