<b>Applying regression models with skew-normal errors to the height of bedding plants of <i>Stevia rebaudiana</i> (Bert) Bertoni

Abstract

The experiment had the objective of fitting regression models to data of the height of the bedding plants cultivated in three multicellular Styrofoam trays with three different cell volumes. We proposed two types of models in the current experiment. First, we fit a model with normal errors and next a model with a skew-normal distribution of errors. The skew-normal regression was suitable for modelling both cases. First, when the model included the time covariate and next when the cell size covariate was part of the model. However, the value of the parameter l for the multivariate model was very high, which is an indication that the skew-normal model is also not the best. Thus, we suggest further fitting using the skew regression model of t-Student.

Keywords

• skew-normal distribution
• parameter estimation
• regression with skew-normal errors