AIExplainer
Machine Learning Intermediate 2 min read

What is a sampling with replacement?

A method of picking items from a set of candidate items in which the same item can be picked multiple times.

A method of picking items from a set of candidate items in which the same item can be picked multiple times. The phrase "with replacement" means that after each selection, the selected item is returned to the pool of candidate items. The inverse method, sampling without replacement, means that a candidate item can only be picked once. For example, consider the following fruit set:

Suppose that the system randomly picks`fig` as the first item. If using sampling with replacement, then the system picks the second item from the following set:

Yes, that's the same set as before, so the system could potentially pick`fig` again. If using sampling without replacement, once picked, a sample can't be picked again. For example, if the system randomly picks`fig` as the first sample, then`fig` can't be picked again. Therefore, the system picks the second sample from the following (reduced) set:

The word replacement in sampling with replacement confuses many people. In English, replacement means "substitution." However, sampling with replacement actually uses the French definition for replacement, which means "putting something back." The English word replacement is translated as the French word remplacement. ---