I am trying to standardize a dataset in Weka. I was able too use to standardize function however the results which I have found using Excel and using Weka were little different.
Following are the screenshots:
Standardized data given by Weka
Manual Excel results
Formula Used for calculating manual results:
z = (x-mean)/SD z = Std value x = value to be standardized mean = mean of dataset SD = standard deviation
I would like to know the formula which Weka uses to calculate the standardized value.
Any help is appreciated!!
To get the formula that weka usage you need to go through the source code that weka provides.
You may be able to get the formula you are looking for.
I checked using Python and NumPy to do the standardization procedure. Weka (v3.6.12) uses indeed
z = (x - mean) / std
std is the standard deviation. Be sure that your
SD corresponds indeed the standard deviations (and not the variances, for instance).