Home » excel » excel – Formula used by Weka for Standardization of data

excel – Formula used by Weka for Standardization of data

Posted by: admin May 14, 2020 Leave a comment

Questions:

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:
``````

Initial Data

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!!
Thanks!!

How to&Answers:

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.

Answer：

I checked using Python and NumPy to do the standardization procedure. Weka (v3.6.12) uses indeed

``````z = (x - mean) / std
``````

where `std` is the standard deviation. Be sure that your `SD` corresponds indeed the standard deviations (and not the variances, for instance).