Pengaruh Metode Demonstrasi terhadap Daya Nalar Matematis Siswa Sekolah Menengah

Penelitian ini bertujuan untuk mengetahui pengaruh metode demonstrasi terhadap daya nalar siswa pada materi garis dan sudut. Penelitian ini merupakan penelitian eksperimen semu dengan nonequivalent control group design. Kelas VII A (37 siswa) dan VII B (37 siswa) pada salahsatu SMP di Lombok Tengah digunakan sebagai sampel yang diambil secara purposive sampling. Data penelitian dikumpulkan menggunakan instrumen tes berbentuk essai. Data daya nalar siswa dianalisis secara statistic menggunakan uji Z. Berdasarkan hasil tes akhir, rata-rata daya nalar siswa pada kelas eksperimen sebesar 76,95 dan pada kelas kontrol sebesar 60,56. Hasil uji-Z daya nalar siswa diperoleh Zhitung  sebesar 0,579 lebih besar dari Ztabel sebesar 1,96 dan hasil, maka Ho ditolak, sehingga dapat disimpulkan bahwa terdapat pengaruh metode demonstrasi terhadap daya nalar siswa sekolah menegah. The Effect of the Demonstration Method on Students' Mathematical Reasoning Ability in Secondary School Abstract This study aims to determine the effect of the demonstration method on students' reasoning abilities in the topic of lines and angles. This research employs a quasi-experimental design with a nonequivalent control group. Class VII A (37 students) and VII B (37 students) in one of the middle schools in Central Lombok were selected as the sample using purposive sampling. Research data was collected using an essay test instrument. Students' reasoning abilities data were statistically analyzed using the Z-test. Based on the final test results, the average reasoning ability score of the experimental group was 76.95, while that of the control group was 60.56. The Z-test results for students' reasoning abilities yielded a calculated Z value of 0.579, which is greater than the critical Z value of 1.96. As a result, the null hypothesis (Ho) is rejected, leading to the conclusion that there is an influence of the demonstration method on the reasoning abilities of secondary school students.