Deng, Leyi, Xiaowei Feng, Yunya Mao, and Zijia Wan. 2026. “Deconstructing the Friday the 13th Effect: Evidence from Dummy-Variable Regression, Wavelet Analysis, and XGBoost Prediction”. Scientific Journal of Intelligent Systems Research 8 (5): 42-56. https://doi.org/10.54691/rp81mr64.