Forecast of the Average Monthly Retail Price of Gasohol 95 in Bangkok
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Abstract
This research aimed to forecast the prices of gasohol 95 using the average monthly retail prices in Bangkok, obtained from the Bank of Thailand website, covering the period from January 2003 to October 2022- a total of 238 months. The time series was divided into two sets. The first 236 months (January 2003 to August 2022) were used to develop forecasting models using four statistical methods: the Box-Jenkins method, Holt’s exponential smoothing method, Brown’s exponential smoothing method, and the damped trend exponential smoothing method. The remaining two months (September to October 2022) were used to compare the accuracy of the models based on the lowest mean absolute percentage error (MAPE) and root mean square error (RMSE). The study found that the damped trend exponential smoothing method was the most accurate, with an MAPE of 2.4430 and an RMSE of 0.8786. The forecast model was shown as follows:
Y^t+m = 37.35001-2.70003 ∑ i=1 m (0.40016)i
where m = 1 represented September 2022.
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References
Ministry of Energy, Energy Vocabulary to Know, Available Source: http://www.eppo.go.th/Energy_Dict/G.htm , December 9, 2022. (in Thai)
Yukon, 91/95 Alternately Add Oil. What's Wrong? Available Source: https://www.yukonlubricants.com/what-wrong-with-filling-up-with-oil/ , December 9, 2022. (in Thai)
Bank of Thailand, Prices of Major Industrial Commodities. Available Source: https://www.bot.or.th/App/BTWS_STAT/statistics/ReportPage.aspx?reportID=90&language=th , December 8, 2022. (in Thai)
RYT9, In 2022 Why is the World Oil Price Dropping? Thailand's Not Decreasing? Available Source: https://www.ryt9.com/s/prg/3307823 , December 9, 2022. (in Thai)
Investing.com, 6 Factors Causing Crude Oil Prices to Fluctuate Throughout 2021. Available Source: https://th.investing.com/analysis/article-200438822 , December 9, 2022. (in Thai)
Keerativibool, W., 2013, Forecasting model for the retail prices of gasohol 91 in Bangkok and peripheral areas, Thaksin. Univ. J. 16: 1-10. (in Thai)
Keerativibool, W., 2013, Forecasting model for the retail prices of gasohol 95 in Bangkok and peripheral areas, KMUTT Res. Dev. J. 36(4): 423-438. (in Thai)
Box, G.E.P., Jenkins, G.M., Reinsel, G.C. and Ljung, G.M., 2015, Time Series Analysis: Forecasting and Control, 5th Ed., Prentice Hall, New Jersey, 712 p.
Bowerman, B.L. and O’Connell, R.T., 2000, Forecasting and Time Series: An Applied Approach, 3rd Ed., Duxbury Press, California, 726 p.
Ket-iam, S., 2003, Forecasting Technique, 2nd Ed., Thaksin University, Songkhla, 295 p. (in Thai)
Manmin, M., 2006, Time Series and Forecasting, Foreprinting, Bangkok, 448 p. (in Thai)
