CODEWITHSUNDEEP
r
SangKwang Kevin Lee
SangKwang Kevin Lee

Reputation: 21

Plotting the density of Cauchy distribution

I have been asked to plot the density of the Cauchy distribution with mean 0, bewteen -5 and 5, and to overlay this with the density of the normal distribution with mean 0 and standard deviation 1.2. And I don't even know where to start.. any help?

Upvotes: 1

Views: 8850

Answers (1)

Andy Barbour
Andy Barbour

Reputation: 8893

Look at the documentation for the Cauchy distribution with ?dcauchy. In fact, that's the function which calculates the Cauchy density function at a location x0, not a mean (as @Dason and @iTech) mention; it is certainly defined for x0=0 though.

The equivalent function for the normal distribution is dnorm, and a plot might look like this:

x<-seq(-10,10,by=0.1)
plot(x, dnorm(x),type="l")
lines(x, dcauchy(x),col="red")

Cauchy dist for x0=0 overlain on a Normal dist.

Note the seq command is somewhat arbitrary: it just creates a vector with evenly spaced values from -10 to 10, at intervals of 1/10.

Good luck on the rest of your homework.

Update:

Here's a simpler way using plot.function:

plot(dnorm, -10, 10, n=1001)
plot(dcauchy, -10, 10, n=1001, col='red', add=TRUE)

Upvotes: 7

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