Z Test on Survey Data - Trying to represent the frequencies of a response as a percentage of total responses in Spotfire

Hi All

The data below relates to survey responses on individual products P1,P2,P3,P4. Rating products from 7 excellent down to 1 not so great.

I am trying to test the significance in terms of difference between frequencies of response/score for product 1 vs product 2 based on rating given. (Expressed as a %)

So for example Product 1 is given a score of 3 and Product 2 is given a 6 by the same person, I would like to represent these values as a percentage and then subtract them from each other. Any idea's on how I might be able to do that in Spotfire would be much appreciated.


Survey Data