Umarov , T. . . “STATISTIKADA KICHIK KVADRATLAR USULI VA UNING TATBIQLARI”. Pedagogy and Psychology in the Modern World: Theoretical and Practical Research, vol. 3, no. 13(Special Issue), Dec. 2024, pp. 153-6, https://www.inlibrary.uz/index.php/zdpp/article/view/57979.