Qualitative variables
Définition : Qualitative variables
They are impossible to measure, they are characterised by their belonging to classes (or categories) called modalities.
E.g. “gender” is a qualitative variable with two modalities: female or male.
“Boroughs of New York City “ is a qualitative variable with five modalities: The Bronx, Brooklyn, Manhattan, Queens, and Staten Island.
Qualitative variables can be just plain nominal (they are just a collection of different names), or have an ordinal scale, meaning that the value of the variable is a rank of order.
Exemple :
E.g. to the question “How do you like this product?” with the following possible answers “I like it so much!”, “I am indifferent”, “I feel extremely offended” The order of preference provides the ranking (note the carefully crafted wording in order to stress the author's inductive influence over the results).
In a less apparent manner, the variable “age” can be qualitative and ordinal when presented in such a form: “less than 20 years old”, “20-29 years old”, “30-44 years old”, “45-59 years old”, “60 years old and more”.
