Penerapan Data Mining menggunakan Algoritme C4.5 dalam Penentuan Jurusan Siswa SMA Negeri 2 Surakarta

Data mining is the process of exploration of the large-sized data to determine patterns in decision-making. One techniques in decision making is classification. Classification is a technique in data mining by applying decision tree method for forming into groups or classes. Algorithm C4.5 is used in the algorithm decision tree. In education areas, the process of determining the student major is the important thing to be decided correctly. The purpose of this research is to determine the placement of students SMA using algorithms C4.5. Based on the discussion it can be concluded that the algorithm is C4.5 can be used in the classification of majors because it has high accuracy. In this study, the determination of the majors is obtained by counting the number of cases of each attribute science and social studies, entropy, gain, split info, and gain ratio. The test results of students at SMA Negeri 2 Surakarta on testing data is performed five times randomly, which is obtained an average percentage of 86.82% accuracy with recall 92.19%, and precision 88.17% . While the test results overall percentage accuracy of 89.78%. Keywords: data mining, classification, algorithm c4.