Article Per Year (5 Year)
p-Index From 2021 - 2026
0.444
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This Author published in this journals
All Journal International Journal of Quantitative Research and Modeling
Alim Jaizul Wahid
Master's Program of Mathematics, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Jatinangor, West Java, Indonesia
Computer Science & IT Decision Sciences, Operations Research & Management Engineering Environmental Science Physics

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The Effect of Double Date Discounts on Sales Levels In E-Commerce Shopee (Case Study on Students of Padjadjaran University in Jatinangor) Alim Jaizul Wahid; Salwa Cendikia Millantika; Asep Kuswandi Supriatna
International Journal of Quantitative Research and Modeling Vol. 5 No. 4 (2024): International Journal of Quantitative Research and Modeling
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijqrm.v5i4.835

Abstract

This study aims to analyze the impact of double date sale discounts on sales levels on the Shopee e-commerce platform, focusing on students from Universitas Padjadjaran in Jatinangor, who are primarily from the millennial and Generation Z cohorts. The method used is simple linear regression, linking discount variables to sales. Additionally, the study conducts classical assumption testing to ensure the models validity and sensitivity analysis to assess the effect of parameter changes on the predicted outcomes. The results show that double date sale discounts significantly influence sales, with the double date sale coefficient (eta_1) being highly sensitive to changes. The regression model yields a low MSE, indicating good prediction accuracy. While changes in the intercept (eta_0) also affect the predictions, the impact is smaller compared to changes in the double date sale coefficient.
Efficient Frontier Analysis of Islamic and Conventional Bank Stock Portfolios: Evidence from Four IDX-Listed Issuers Using the Markowitz Model Dede Irman; Alim Jaizul Wahid
International Journal of Quantitative Research and Modeling Vol. 7 No. 2 (2026): International Journal of Quantitative Research and Modeling (IJQRM)
Publisher : Research Collaboration Community (RCC)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46336/ijqrm.v7i2.1340

Abstract

This study investigates and compares the portfolio performance of Islamic and conventional bank stocks listed on the Indonesia Stock Exchange (IDX) using the Markowitz Mean-Variance optimization model. Four issuers were selected: PT Bank Rakyat Indonesia Tbk (BBRI), PT Bank Mandiri Tbk (BMRI), PT Bank Rakyat Indonesia Syariah Tbk (BRIS), and PT Bank Pembangunan Daerah Banten Tbk (BPAA), representing two conventional and two Islamic banking stocks respectively. Daily closing price data spanning from January 2021 to December 2023 (756 trading days) were employed to compute expected returns, variance, covariance, and correlation coefficients. Two optimal portfolios were constructed for each category: the Minimum-Variance Portfolio (MVP) and the Maximum-Sharpe Portfolio (MSP). Performance evaluation was carried out through multiple metrics including the Sharpe Ratio, Treynor Ratio, Jensen's Alpha, and Sortino Ratio. Results indicate that Islamic bank portfolios consistently outperform conventional bank portfolios on a risk-adjusted basis. The Maximum-Sharpe Islamic portfolio achieved a Sharpe Ratio of 1.765 compared to 1.342 for its conventional counterpart. These findings suggest that Islamic banking stocks, with their inherently lower leverage and prohibition on speculative instruments, exhibit more favourable risk-return characteristics, providing actionable insights for investors seeking Shariah-compliant investment alternatives.
Co-Authors Asep Kuswandi Supriatna Dede Irman Salwa Cendikia Millantika