2 of 2 people found this helpful
First, read this: Percentile - Wikipedia, the free encyclopedia
Given a data set of values:
The % of total will be SUM([Value])/TOTAL(SUM([Value])), so the given value divided by the 2+3+3+4+8 = 20, so the results of a % of total will be:
Whereas the percentile table calculation is using RANK_PERCENTILE(SUM([Value])) and returns the "position" of the value. The way I like to think of this is that if I make an ordered line of values going from the lowest to the highest 2,3,3,4,8 then I'm going to split that into evenly-spaced segments. The middle value is the median and that's the 50th percentile, in this case there are 5 values so the median is the 3rd value and that is 3. So anything with a 3 is 50th percentile. Using this data set Tableau returns:
Tableau also has a WINDOW_PERCENTILE() table calculation function that returns the value for a given percentile (so it's the inverse of RANK_PERCENTILE), and a PERCENTILE() function that is like WINDOW_PERCENTILE() but as a regular aggregate measure.
1 of 1 people found this helpful