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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