Univariate Time-Series Analysis of Second-Hand Car Importation in Zambia
Univariate Time-Series Analysis of Second-Hand Car Importation in Zambia作者机构：Department of Mathematics and Statistics Mulungushi University Kabwe Zambia
出 版 物：《Open Journal of Statistics》 (统计学期刊（英文）)
年 卷 期：2017年第7卷第4期
页 面：718-730页
学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学]
主 题：Zambia Importation Second Hand Car Exponential Smoothing Models ARIMA Models Forecasting
摘 要：Zambia largely depends on the international second-hand car (SHC) market for their motor vehicle supply. The importation of Second hand Cars in Zambia presents a time series problem. The data used in this paper is monthly data on SHC importation from 1st January, 2014 to 31st December, 2016. Data was analyzed using Exponential Smoothing (ES) and Autoregressive Integrated Moving Average (ARIMA) models. The results showed that ARIMA (2, 1, 2) was the best fit for the SHC importation since its errors were smaller than those of the SES, DES and TES. The four error measures used were Root-mean-square error (RMSE), Mean absolute error (MAE), Mean percentage error (MPE) and Mean absolute percentage error (MAPE). The forecasts were also produced using the ARIMA (2, 1, 2) model for the next 18 months from January 2017. Although there is percentage increase of 90.6% from November 2015 to December 2016, the SHC importation generally is on the decrease in Zambia with percentage change of 59.5% from January 2014 to December 2016. The forecasts also show a gradual percentage decrease of 1.12% by June 2018. These results are more useful to policy and decision makers of Government departments such as Zambia Revenue Authority (ZRA) and Road Development Agency (RDA) in a bid to plan and execute their duties effectively.
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