The SDL Component Suite is an industry leading collection of components supporting scientific and engineering computing. Please visit the SDL Web site for more information....



StandardizeNumCellColumns


Unit:SDL_datatable
Class:TDataTable
Declaration:procedure StandardizeNumCellColumns (means, stddevs: TVector);

The method StandardizeNumCellColumns standardizes the data columns of the numeric cells (cells which are neither marked as csNAN, nor as csUndefined and which belong to either interval or ratio scaled variables) of the data table. This means that the numeric elements of the data matrix are transformed in a way that each column of the matrix has a zero mean and a unit standard deviation. The means and the standard deviations of all columns are returned in the parameters means and stddevs. Columns which contain nominal or ordinal values are left unchanged. StandardizeNumCellColumns triggers the OnChange event.

Please note that size of the vector parameters means and stddevs has to be equal to NrOfColumns. The parameters means and stddevs may be set to NIL, if these results are not needed.

Hint: Background information on the standardization of data can be found in Fundamentals of Statistics.



Last Update: 2012-Oct-20