The normalization is to be done by considering the difficulty level of each set, since the questions may be different in different sets and difficulty level of a particular set may be different from other sets.

How normalization is done in database?

Normalization is the process of organizing data in a database. This includes creating tables and establishing relationships between those tables according to rules designed both to protect the data and to make the database more flexible by eliminating redundancy and inconsistent dependency.

How normalization is done in machine learning?

Normalization is a scaling technique in Machine Learning applied during data preparation to change the values of numeric columns in the dataset to use a common scale. It is not necessary for all datasets in a model. It is required only when features of machine learning models have different ranges.