TY - JOUR
T1 - Modeling Average Prices of Garlic in Indonesia
AU - Widodo, Agus AU - Kusdarwati, Heni AU - Handoyo, Samingun
JO - Journal of Engineering and Applied Sciences
VL - 14
IS - 21
SP - 7943
EP - 7950
PY - 2019
DA - 2001/08/19
SN - 1816-949x
DO - jeasci.2019.7943.7950
UR - https://makhillpublications.co/view-article.php?doi=jeasci.2019.7943.7950
KW - Garlic price
KW -ARIMA Model
KW -forecasting
KW -time series
KW -ACF
KW -PACF
AB - The high consumption of garlic in Indonesia cannot be followed by an adequate supply of garlic, so
that, until now Indonesia still imports garlic. Policy formulation in the field of essential goods requires accurate
information The study discusses modeling stages and develops of the average prices of garlic in Indonesia with
the ARIMA Box-Jenkins method. The monthly data of average prices of garlic in the January 2014 to June 2018
period obtained from the directorate of basic goods and essential goods of the Ministry of Trade of the
Republic of Indonesia. Model development uses data from the period of January 2014 to December 2017 which
were referred to as in-sample data while data from January 2018 to June 2018 period as out-sample data to
evaluate model performance. Modeling begins with the transformation of time series data into stationary time
series data, identification pattern of common models via. plot of ACF and PACF values, estimating and testing
of parameters to obtain a feasible model, then continued with a model diagnostic test and finally, gets the best
model is ARIMA Model (1, 1.0). Based on the best model, the comparison plot was made between the actual
and predicted values that were resulted by both of in-sample and out-sample data and also was calculated the
coefficient of determination (R2) as accuracy measure. The actual and predicted values plot in the in-sample
data are very coincident and produce R2 which is quite high at 91. 4%. However, the performance of the ARIMA
(1, 1, 0) Model is moderate when forecasting out-sample data whicch R2 is 59.8%.
ER -