REGRESSION MODELS BY GRETL AND R STATISTICAL PACKAGES FOR DATA ANALYSIS IN MARINE GEOLOGY

Authors : Polina LEMENKOVA

Pages : 39-59

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Publication Date : 2019-06-30

Article Type : Research Paper

Abstract :Gretl and R statistical libraries enables to perform data analysis using various algorithms, modules and functions. In this study, the geospatial analysis of example case study of Mariana Trench, a deep-sea hadal trench located in west Pacific Ocean, was performed using multi-functional combined approach of both Gretl and R libraries. The study aim was to model and visualize trends in variations of the trench’s properties: bathymetry insert ignore into journalissuearticles values(depths);, geomorphology insert ignore into journalissuearticles values(steepness gradient);, geology, volcanism insert ignore into journalissuearticles values(igneous rocks);. The workflow included following statistical methods computed and visualized in Gretl and R libraries: 1); descriptive statistics; 2); box plots, normality analysis by quantile-quantile insert ignore into journalissuearticles values( QQ ); plots; 3); local weighted polynomial regression model insert ignore into journalissuearticles values(loess);, 4); linear regression by several methods: weighted least squares insert ignore into journalissuearticles values(WLS); regression , ordinary least squares insert ignore into journalissuearticles values(OLS); regression , maximal likelihood linear regression and heteroskedasticity regression model; 5); confidence ellipses and marginal intervals for data distribution; 6); robust estimation by Nadaraya–Watson kernel regression fit; 7); correlation analysis and matrix. The results include following ones. First, the geology of the trench has a correlation with a slope angle gradient and igneous rocks insert ignore into journalissuearticles values(volcanism effect);. Second, the sedimentation is distributed unequally by tectonic plates. Third, there is a correlation between the slope gradient and aspect degree. Forth, geospatial analysis of the bathymetry shows that the deepest part of the trench is located in the south-west.
Keywords : Statistical Analysis, Gretl, R, Regression Model, Spatial Analysis, Geology