The data used in this study were secondary data and collected from the GREEN
zone ETD, HTAR. There are 21 samples which is equivalent to 21days during month
of January 2013. Only 21 samples were collected due to problemoccured and system
maintenance during the recording of the data. This month has been chosen since there
are few seasonal holidays such as festive season and school holiday. Therefore, the
demand for ETD is quite high in month of January 2013.