Figure 6 and Figure 9 compare the actual weekly prices with the predicted values from the Box-Jenkins and the
artificial neural networks, respectively. Although the differences are small, it is noteworthy that the predicted values for all
4 categories are consistently below the actual values. This suggests that the underlying forces and structure that produced
the observed time series data may have shifted slightly in recent months. Prices of rice are determined by supply and
demand. Recently, the USDA reported that world’s rice ending stocks are at 3% below the previous month and projected to
be 11% below the previous marketing period. The world’s rice ending stocks are the lowest since 1982/83 [Coats, 2006].
World rice consumption exceeding production, weather conditions reducing production, continued strong global growth, the
weakening of the US dollar in the 2006-07 marketing period, changing demographics, have contributed to bullish rice prices
in recent months [Bennett,2006].