., Khairudin, et al. “Developing Educational Statistics Module by Using Problem-Based Learning (PBL) for the Students of the Faculty of Teacher Training and Education of Bung Hatta University, Padang, Indonesia”. International Journal of Engineering & Technology, vol. 7, no. 4.9, Oct. 2018, pp. 220-5, https://doi.org/10.14419/ijet.v7i4.9.21084.