Rescaling is a process used in data preprocessing to transform numerical variables to a different scale. For example, we may convert dollars to euros to explains something to a colleague in Germany.

We'll talk about many types of rescaling and data transformation throughout the class. For example,  Normalization or standardization are types of rescaling that transform numerical variables to a common scale. 

For example, if 4 eggs cost $2, 12 eggs cost $5, and 24 eggs costs $11, we could calculate the price per egg to make sure we're getting the best deal.