Plot normal distribution into existing plot
<p>I have this ggplot </p>

<pre><code>ggplot(data = ph, aes(x = index1)) + geom_density()
</code></pre>

<p>and I would like to add a normal distribution with the same mean <code>(= 2.71)</code> and standard Deviation <code>(= 0.61)</code>.</p>

<p>I created the normal distribution with:</p>

<pre><code>nd1 &lt;- rnorm(n = 100000, mean = 2.71), sd = 0.61)
nd1plot &lt;- qplot(nd1, geom = "density") + theme_classic() +  ggtitle("Normalverteilung")
</code></pre>

<p>But now I don't know how to add it to my existing plot. Can anyone help me with this issue?</p>