Dealing with the Contamination and Heterosedasticity Proplems In the CRD by Using the Wavelet Filter

This paper deals with the proplems of contamination and heteroscedasticity , by using a method (the Direct Wavelet Filter that used which some method of thresholding) and comparing it with some classical method of transformation in the complete randomized design , through a Matlab code that perform the filtering process , also SPSS was also used.