Stochastic independence of events is not only important concept but useful role in statistics and probability. In this paper, we investigate and analyze the definition of stochastic independence used in the middle and high school mathematics education course. and We investigated that students know concept of independent events. As a result, students was a lack of understanding about the concepts associated with independence of events. and the connection between concepts associated with independent of events were partially. Also, Connections between lower-level concepts and high-level concepts can be done well so teaching-learning was needed.