Pre-processing

Step (2) Pre-processing as an important step in data processing (normalization) is performed on the data. The variable measured the deviation from the mean in units of standard deviation is called a Standardized variable, is a quantity without any dimensions, as per given formula:

where z is a standard score. X¯ is the mean of the data. S is the standard deviation of the data.

If the deviations from the mean are given in units of the standard deviation, there are said to be expressed in standard scores. These values are practical in comparing distributions (Spiegel and Stephens 1999). The rational reason for using this method is that the effects of the altitudes in different channels should be eliminated. In this stage, as a result of similar altitudes, the only impact on calculations is dynamic effects.