# How to Add Vertical Line to Histogram in R

You can use the following methods to add a vertical line to a histogram in R:

Method 1: Add Solid Vertical Line at Specific Location

```abline(v=2)
```

This syntax adds one vertical line to the histogram at x=2.

Method 2: Add Customized Vertical Line at Specific Location

`abline(v=mean(data), col='red', lwd=3, lty='dashed')`

This syntax adds one vertical red dashed line with a width of 3 at the mean value of the histogram.

Method 3: Add Multiple Customized Vertical Lines

```abline(v=quantile(data, .25), col='red', lwd=3)
abline(v=quantile(data, .75), col='blue', lwd=3)```

This syntax adds a red vertical line at the first quartile and a blue vertical line at the third quartile of the histogram.

The following examples show how to use each method in practice.

## Example 1: Add Solid Vertical Line at Specific Location

The following code shows how to create a histogram and add a vertical line at x=2:

```#make this example reproducible
set.seed(1)

#create data
data <- rnorm(n=1000, mean=5, sd=2)

#create histogram to visualize distribution of data
hist(data)

abline(v=2)
``` ## Example 2: Add Customized Vertical Line at Specific Location

The following code shows how to create a histogram and add one vertical red dashed line with a width of 3 at the mean value of the histogram:

```#make this example reproducible
set.seed(1)

#create data
data <- rnorm(n=1000, mean=5, sd=2)

#create histogram to visualize distribution of data
hist(data)

#add vertical line at mean value
abline(v=mean(data), col='red', lwd=3, lty='dashed')
``` ## Example 3: Add Multiple Customized Vertical Lines

The following code shows how to create a histogram and add a red vertical line at the first quartile and a blue vertical line at the third quartile of the histogram.

```#make this example reproducible
set.seed(1)

#create data
data <- rnorm(n=1000, mean=5, sd=2)

#create histogram to visualize distribution of data
hist(data)

#add vertical lines at 1st and third quartiles
abline(v=quantile(data, .25), col='red', lwd=3)
abline(v=quantile(data, .75), col='blue', lwd=3)
``` 