“…In addition, the distribution of the residual term is altered which can be advantageous, especially if the distribution of the original residual term, ε(k), is non-Gaussian [Ljung, 1999]. Several types of transform have been applied in time series forecasting such as Principle Component Analysis (PCA) [Hiden et al, 1999], Independent Component Analysis (ICA) [Roberts et al, 2004], the Fourier Transform (FT) [Schoukens & Pintelon, 1991], the Wavelet Transform (WT) [Yao et al, 2000] and the Wavelet Packet Transform (WPT) [Saito & Coifman, 1997;Roberts et al, 2004;Milidiú et al, 1999;Nason & Sapatinas, 2001] among others. However, the WT and WPT would seem ideal for time series forecasting as unlike PCA, ICA and the FT, some time information is preserved in the transformed variables.…”