其它
\textbf{Which of the following is/are categorical variable(s)?}  \textbf{I. The mean of Grade 1 boys' heights}  \textbf{II. The colors of jackets in the class}  \textbf{III. The types of pens in a stationary store} 
Overseas Competition->Knowledge Point->Calculation Modules
\textbf{A categorical variable is defined by the set of groups or categories (qualitative values) that individuals are placed into; it is not a numerical value. The mean of~ Grade 1 boys' heights is a number. The colors of jackets in the class and the types of pens in a stationary store cannot be described by numbers.~} 