Hi,

I would like to draw a line on this histogram:

hist(rnorm(100, mean=15, sd=1), xlim=range(11:19), main="Size 100", xlab="x")

The line must show that this histogram is a Gaussian Curve!

I hope the question is understandable...

Hi,

I would like to draw a line on this histogram:

hist(rnorm(100, mean=15, sd=1), xlim=range(11:19), main="Size 100", xlab="x")

The line must show that this histogram is a Gaussian Curve!

I hope the question is understandable...

That's a little tricky since the area under a Gaussian integrates to one, while a histogram plots frequencies/counts.

As @EconomiCurtis points out, you have to change from a frequency histogram to a density histogram. It's all downhill from there:

```
data <- rnorm(100, mean=15, sd=1)
hist(data, xlim=range(11:19), main="Size 100", xlab="x", freq=FALSE)
curve(dnorm(x,mean=mean(data),sd=sd(data)), add=TRUE,col="red")
```

Obligatory Stack Overflow discussion: Fitting a density curve to a histogram in R - Stack Overflow

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You can also do it with `ggplot2`

using `stat = density`

and `stat_function()`

:

```
library(dplyr)
library(ggplot2)
set.seed(100)
rnorm(100, mean=15, sd=1) %>%
as_tibble() %>%
ggplot(aes(value)) +
geom_histogram(stat = "density") +
stat_function(fun = function(x) {dnorm(x, 15, 1)}, color = "red") +
lims(x = c(11, 19))
```

which gives you this:

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