You can use the rnorm() and runif() functions to generate random values in R.

Here’s the difference between the two functions:

The rnorm(n, mean, sd) function is used to generate n random values from a normal distribution with a specific mean and standard deviation.

The runif(n, min, max) function is used to generate n random values from a uniform distribution with a specific minimum and maximum value.

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

Example 1: How to Use rnorm() in R

The following code shows how to use the rnorm() function to generate 100 random values from a with a mean of 10 and a standard deviation of 2:

#make this example reproducible
set.seed(0)

#create vector of 100 random values from normal distribution
random_values <- rnorm(n=100, mean=10, sd=2)

#view first six values
head(random_values)

[1] 12.525909  9.347533 12.659599 12.544859 10.829283  6.920100

We can also use the hist() function to create a histogram to visualize the distribution of random values we just generated:

#create histogram to visualize distribution of values
hist(random_values)

The result is a histogram that displays the distribution of the 100 values from the normal distribution.

Notice that the histogram has a bell shape and the mean is located around 10, the exact value that we specified for the mean of the distribution.

Example 2: How to Use runif() in R

The following code shows how to use the runif() function to generate 100 random values from a with a minimum value of 5 and a maximum value of 25:

#make this example reproducible
set.seed(0)

#create vector of 100 random values from uniform distribution
random_values <- runif(n=100, min=5, max=25)

#view first six values
head(random_values)

[1] 22.933944 10.310173 12.442478 16.457067 23.164156  9.033639

We can also use the hist() function to create a histogram to visualize the distribution of random values we just generated:

#create histogram to visualize distribution of values
hist(random_values)

The result is a histogram that displays the distribution of the 100 values from the uniform distribution.

Notice that the histogram ranges from 5 to 25, which represent the minimum and maximum values that we specified in the runif() function.