Randomly sampling from a Uniform Distribution between -3 and 5

We often need to think about the distribution of samples from a population. In this very simple example, we randomly sample two observations from a random variable X~U(-3, 5). That is, X follows a uniform distribution between -3 and 5.
Statisticians often use the sample mean as an estimator of the population average, or expectation. This exercise provides the first step towards thinking about the distribution of the sample mean, by considering the distribution of the sum of the two observations.