Journal of Mathematics, Computation and Statistics (JMATHCOS)
Vol. 9 No. 2 (2026): Volume 09 Issue 02 (June 2026)

Semiparametric Spline Regression with Moving Average Smoothing Under Heteroscedastic Errors for Childhood Stunting Prevalence in Indonesia

Jiran Julita (Institut Teknologi Sepuluh November)
Jerry Dwi Trijoyo Purnomo (Institut Teknologi Sepuluh November)
I Nyoman Budiantara (Institut Teknologi Sepuluh November)



Article Info

Publish Date
23 May 2026

Abstract

Stunting prevalence remains a critical public health issue in Indonesia due to its long-term impact on child development and human capital. This study aims to model stunting prevalence using a semiparametric regression approach with truncated spline functions, which allows for capturing both linear and nonlinear relationships between variables. The percentage of poor population is treated as the parametric component, while immunization coverage is modeled as the nonparametric component. Model estimation is initially performed using Ordinary Least Squares, where the best model is obtained with two knot points and a minimum Generalized Cross Validation value of 21.74771. However, residual diagnostics indicate the presence of heteroscedasticity. To address this issue, Weighted Least Squares with a moving average approach is applied. The results show that the optimal weighted model uses three knot points with a cubic spline, producing a lower GCV value of 14.48820 and a higher coefficient of determination of 86.78 percent compared to 61.98 percent in the OLS model. Furthermore, all residual assumptions are satisfied under the weighted approach. These findings indicate that the WLS method with moving average provides a more accurate, stable, and reliable model for analyzing stunting prevalence.  

Copyrights © 2026






Journal Info

Abbrev

JMATHCOS

Publisher

Subject

Mathematics

Description

Fokus yang didasarkan tidak hanya untuk penelitian dan juga teori-teori pengetahuan yang tidak menerbitkan plagiarism. Ruang lingkup jurnal ini adalah teori matematika, matematika terapan, program perhitungan, perhitungan matematika, statistik, dan statistik ...