Understanding dnorm and geom_density

Question

x <- seq(-4, 4, length.out = 100)
data.frame(x,  f = dnorm(x)) %>%
     ggplot(aes(x, f)) +
     geom_line()

imho, this should give the exact same plot as this:

x <- seq(-4, 4, length.out = 100)
data.frame(x,  f = dnorm(x)) %>%
   ggplot() +
   geom_density(aes(x))

How come it doesn't?

Why should plotting a line give the same thing as estimating the density of some data and then plotting that? — Dason, May 19 '18 at 21:40
Got it. x <- seq(-4, 4, length.out = 100) creates a constantly distributed variable. — Ahsen Majid, May 19 '18 at 21:47

score 2 · Accepted Answer · answered May 19 '18 at 21:53

2

You are probably looking for stat_function

x <- seq(-4, 4, length.out = 100)
data.frame(x,  f = dnorm(x)) %>%
     ggplot(aes(x, f)) +
     geom_line() + 
     stat_function(fun=dnorm, geom="line", col=2, lty=2)

answered May 19 '18 at 21:53

adibender

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Understanding dnorm and geom_density

1 Answers1