Skip to content

Latest commit

 

History

History
20 lines (10 loc) · 2.58 KB

README.md

File metadata and controls

20 lines (10 loc) · 2.58 KB

Chapter 3 Robust Estimators in Multiple Regression


Atkinson,A.C., Riani,M., Corbellini,A., Perrotta D., and Todorov,V. (2024), Applied Robust Statistics through the Monitoring Approach, Heidelberg: Springer Nature.

Abstract

The first five sections describe multiple regression with least squares, including methods for outlier detection. Section 3.6 introduces three distinct approaches to robust regression: (i) soft trimming, or downweighting, which extends the M-estimation of Chapter 2 to regression, principally S-estimation (Section 3.8); (ii) hard trimming, Least Trimmed Squares (LTS, Section 3.11) in which a specified proportion of the observations is trimmed and (iii) adaptive hard trimming, the Forward Search (FS, Section 4.1). This monitoring method is explored more thoroughly in Chapter 4. Unlike the FS, the methods in (i) and (ii) provide a single robust analysis under chosen specified conditions. That for LTS depends on the chosen trimming proportion, which should, hopefully, trim all outliers and fit the model to the uncontaminated data. For the downweighting methods in (i) the severity of downweighting is determined by the choice of tuning constants to give desired robustness properties. The calculations are described in Section 3.9. The algorithm for S-estimation is in section 3.10 with that for LTS in Section 3.11.1. Further developments of M-estimation (MM- and $\tau$-estimators) are described in 3.12,1 and 3.12.2. Reweighted LTS estimators are introduced in 3.12.3. Section~3.13 concludes the chapter with comparisons of traditional robust data analyses for a single specified target of robustness.

Code to reproduce Figures and Tables in this Chapter

FileName Description Open in MATLAB on line Jupiter notebook
ARtraditional.m AR data.
This function creates Figures 3.1-3.5, 3.8 and 3.9. Figures 3.1-3.5: traditional non robust analysis. Figures 3.8-3.9: traditional robust analysis based on S and MM estimators.
Open in MATLAB Online [ipynb]
consistencyFactor.m Consistency factor, break down point and efficiency.
This file createa Figure 3.6, 3.7, Table 3.2 and 3.3.
Open in MATLAB Online [ipynb]