When choosing a random sample, each population member must have the same chance of being included in the sample. How can we select a random sample in practice?

Manual selection of samples

Using random numbers to select a sample

In practice, random samples are usually chosen by numbering all population members, starting from index 0. Random numbers between 0 and the largest population index are generated to select individuals from the population.

A randomly generated value will identify one individual in the population to sample. If sampling with replacement, further random values are generated to specify further individuals to sample until the required sample size is reached. If sampling without replacement, generated random values are rejected if they have already been chosen, to ensure that no individual is selected more than once.

Selecting a random sample