Which of the following variables is quantitative?

The variable that is quantitative is grade point average. This is because a grade point average (GPA) represents a numerical value that reflects a student's academic performance, often calculated on a standard scale (e.g., 0 to 4.0). It provides a measurable indication of achievement, allowing for mathematical operations such as averaging, comparison, and statistical analysis.

In contrast, color of a car, number of siblings, and favorite subject are categorical variables. The color of a car is a nominal variable, representing categories without any inherent numerical value. Number of siblings may seem quantitative at first glance, but it is actually discrete rather than continuous; while it involves counting, it doesn't reflect a measurement on a continuous scale like GPA does. Favorite subject is also categorical, as it identifies a preference within a set of options without offering numerical information. Thus, grade point average stands out as a true quantitative variable.