ggplot2: histogram with normal curve

r ggplot2 curve
Bloomy picture Bloomy · Aug 6, 2011 · Viewed 86.2k times · Source

I've been trying to superimpose a normal curve over my histogram with ggplot 2.

My formula: 

data <- read.csv (path...)

ggplot(data, aes(V2)) + 
  geom_histogram(alpha=0.3, fill='white', colour='black', binwidth=.04)

I tried several things:

+ stat_function(fun=dnorm)

....didn't change anything

+ stat_density(geom = "line", colour = "red")

...gave me a straight red line on the x-axis.

+ geom_density()

doesn't work for me because I want to keep my frequency values on the y-axis, and want no density values.

Any suggestions?

Thanks in advance for any tips!

Solution found!

+geom_density(aes(y=0.045*..count..), colour="black", adjust=4)

Answer

Carlos Eduardo Vazquez picture Carlos Eduardo Vazquez · Nov 28, 2012

Think I got it:

set.seed(1)
df <- data.frame(PF = 10*rnorm(1000))
ggplot(df, aes(x = PF)) + 
    geom_histogram(aes(y =..density..),
                   breaks = seq(-50, 50, by = 10), 
                   colour = "black", 
                   fill = "white") +
stat_function(fun = dnorm, args = list(mean = mean(df$PF), sd = sd(df$PF)))

enter image description here

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