An interval nonparametric regression method

This paper proposes a nonparametric multiple regression method for interval data. Regression smoothing investigates the association between an explanatory variable and a response variable. Here, each interval variable of the input data is represented by its range and center and a smooth function between a pair of vector of interval variables is defined. In order to test the suitability of the proposed model, a simulation study is undertaken and an application using thirteen project data of the NASA repository to estimate interval software size is also considered. These real data represent variability and/or uncertainty innate to the project data. The prediction quality is assessed by a mean magnitude of relative errors calculated from test data.