dc.description.abstract |
Textiles along with clothing sector are truly considered t he backbone of the world’s economy.
The main objective of this study was Time Series Analysis of the export flat bed sheet and pillow
product of Kombolcha Textile Share Company . The descriptive and inferential statistical techniques
were used for data analysis in this study. Univariate Time series analysis uses only the past
history of the time series forecast plus current and past random error terms. Time series data
used in this analysis consists of the monthly data of 2007 to 2016 on export flat bed sheet and
pillow product univariate secondary data obtained from the monthly report of the Kombolcha
Textile Share Company. The Autocorrelation Function (ACF) and Partial Autocorrelation
Function (PACF) were the most important elements for model identificatio n and AIC and SBC
were also used to select the best fit of model adequacy. Forecasting is the prediction of a future
value Y n +k from a series of n previous values Y 1
, Y 2
, . . . , Y n
. The most common measures of
predictive accuracy were MSE, RMSE, and MAE. The ACF and PACF for the export flat bed
sheet and pillow product were large negative significant spike at lag 1 (this means that the ACF
and PACF of the successive pairs of observations within 1 time period is not within sampling
error of zero). All of the other ACF and PACF for lags 2 to 30 are within the 95% confidence
limits. ARIMA(1,1,1)with corresponding AR(1) and MA(1) were best fit of the Box Jenkins model
or in the mean model ARCH(1)and GARCH(1,1) were also best in the variance model in this
study. The modified Box-Pierce (Ljung-Box) chi-square statistics of 6.5, 12.7, 19.2, and 20.6
give p-values of 0.688, 0.920, 0.974, and 0.999 show that there is good fit of the model. Because
the p-values are quite large (greater than 0.05), since we conclude that the residuals appear to
be uncorrelated. The minimum value of forecasting performance, MAPE=40.3 is better fit of the
model forecasting accuracy. The scaling of Thiel’s inequality coefficient U=0.165 was close to
zero, it is good predictive performance of the model. |
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