This document defines and provides examples of quantitative and qualitative variables. It explains that quantitative variables can be measured numerically, like the number of children in a family, while qualitative variables are categorical, such as car models or types of potatoes. The document then provides steps to classify a variable and diagrams to illustrate the difference. It gives examples of applications of quantitative research in social sciences and findings on its use in sociology journals. In closing, it lists the references used in the presentation.