How to plot a normal distribution by labeling specific parts of the x-axis?

Question

I am using the following code to create a standard normal distribution in R: ``` x <- seq(-4, 4, length=200) y <- dnorm(x, mean=0, sd=1) plot(x, y, type="l", lwd=2) ``` I need the x-axis to be labeled at the mean and at points three standard deviations above and below the mean. How can I add these labels?

Accepted Answer

The easiest (but not general) way is to restrict the limits of the x axis. The +/- 1:3 sigma will be labeled as such, and the mean will be labeled as 0 - indicating 0 deviations from the mean.

```
plot(x,y, type = "l", lwd = 2, xlim = c(-3.5,3.5))
```

Another option is to use more specific labels:

```
plot(x,y, type = "l", lwd = 2, axes = FALSE, xlab = "", ylab = "")
axis(1, at = -3:3, labels = c("-3s", "-2s", "-1s", "mean", "1s", "2s", "3s"))
```

How to plot a normal distribution by labeling specific parts of the x-axis?

Solution

Problem