To differentiate the numerical and categorical data, we must identify what kind of data are we dealing with.
For the numerical data, we can either have an interval or ratio data while for the categorical, we can have the nominal data.
Thus, for the numerical data, an example would be identifying the number of hours of sleep of a person.
Numerical data: How many hours of sleep do you have on a weekday?
For the categorical data, we must make sure that the answers must be from the names of different options. An example would be the color.
Categorical Data: What is your favorite color?
Note that for the hours of sleep, the answers would be numbers while the favorite color would be names of the colors.