Seasonal Analysis for the series of Cost of the Basic Food Basket of Lavras, MG, and its components

Abstract

The effects of seasonal fluctuations caused by weather and natural fluctuations in demand and supply have influenced the price of various agricultural products, leading many times to an oscillation of prices to be mistakenly linked to further factors. In an attempt to better understand how the influence of the seasonal factor works for the prices of agricultural products, this paper has the objective of analyzing the seasonal behavior the Cost of Basic Basket series (basic food) in Lavras, MG, and its components, besides making a comparison between the direct and indirect form of the disseasonalize the series of Cost of Basic Basket. The data were obtained from the UFLA Department of Administration and Economics and cover the period from January 1995 to December 2005. The database consists of the time series of the 17 products that make up the Food Basket of Lavras, plus the series of the Cost of Basic Basket. The results elicited that eleven of the eighteen series analyzed presented identified seasonality, and then for each series models Sarima were adjusted. Finally, by comparing in a directly and indirectly way the removal of seasonality of the series, the research proved that the direct way is more effective.