Analysis of the trend in arrivals and prices of tender coconut in Maddur market, Karnataka

Abstract

The present study analyses the trend in arrivals and prices of tender coconut in the Maddur market by fitting three linear models viz. linear (Straight line), quadratic and exponential models, and three nonlinear models viz. logistics, Gompertz and Richard’s to the annual data on arrivals (In crore nuts) and prices (In rupees per thousand nut) of tender coconuts for the period of 21 year i.e. from 1997-98 to 2017-18. The test statistic to check the goodness of fit of each model was computed using Root Mean Squared Error (RMSE), Mean Absolute Percentage Error (MAPE), and Akaike’s Information Criteria (AIC). The main assumptions of independence of errors and normality distribution of error terms of each model were examined by using respectively the ‘Run-test’ and ‘Shapiro-Wilk test. Based on the lowest value of RMSE, MAPE and AIC, Richard’s model fitted better than other models for arrivals of the tender coconut, and the Quadratic model was found to be the best-fitted model for the prices of the tender coconut in the Maddur market. Based on the overall goodness of criteria the best-fitted model for arrivals could be ranked as follows: Richard’s, logistic, exponential, Gompertz, linear and quadratic models. Trend values obtained by the best-fitted model reveal that both arrivals and prices of tender coconut in the Maddur market have an upward trend.