I am not familiar with SPSS but one thought is that the count() of a measure won't include NULL values for that result for the measure. How does SPSS handle nulls? and do you have any in your data?
also. I'd try to figure this out by using smaller amounts of data to see if they match up when using a single day vs 3 days.. work from 'working' up to not working to help figure out the cause.
Thank you for your reply on this post.
I have now figured out what the formula needs to be.
It is SUM([Measure])/(SUM([Weight]))
As I’d already multiplied my measures by my weight I then needed to divide it by the sum of those weights once it is in Tableau.
I also made sure the sum of my measure times the weight in Excel matched the same output from SPSS before I put it into Tableau.
Thanks again for your input.