Soybean yield modeling using bootstrap methods for small samples

• Main Authors: Gustavo H. Dalposso, Miguel A. Uribe-Opazo, Jerry A. Johann
• Format: Article
• Language: English
• Published: Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria 2016-08-01
• Series: Spanish Journal of Agricultural Research
• Subjects: multiple linear regression; model selection; bootstrap global influence diagnosis; bootstrap confidence intervals
• Online Access: http://revistas.inia.es/index.php/sjar/article/view/8635

One of the problems that occur when working with regression models is regarding the sample size; once the statistical methods used in inferential analyzes are asymptotic if the sample is small the analysis may be compromised because the estimates will be biased. An alternative is to use the bootstrap methodology, which in its non-parametric version does not need to guess or know the probability distribution that generated the original sample. In this work we used a set of soybean yield data and physical and chemical soil properties formed with fewer samples to determine a multiple linear regression model. Bootstrap methods were used for variable selection, identification of influential points and for determination of confidence intervals of the model parameters. The results showed that the bootstrap methods enabled us to select the physical and chemical soil properties, which were significant in the construction of the soybean yield regression model, construct the confidence intervals of the parameters and identify the points that had great influence on the estimated parameters.