Dr Calloway Is in the Process of Classifying and Arranging

Multiple Choice

Dr. Calloway is in the process of classifying and arranging data from his recent observations while on safari in Africa. He has grouped subjects into three classifications: mammals, reptiles, and birds. Dr. Calloway is grouping subjects based on a(n) :

A) interval variable.
B) continuous variable.
C) ordinal variable.
D) categorical variable.