WereKitten on 25 March 2009
@Demotruk
If I say that "user belongs to set N if he owns Z:TP and SMG" then N is equal to the intersection of the set of those who own Z:TP and the set of those who own SMG.
If by hypothesis, as I said previously, there's a strong correlation between those two sets (say 90%), then the size of N is the minimum between the number of owners of Z:TP and the number of owners of SMG, with an error of 10%. That's your 5-8M group.
Your only way out is you think the hypothesis is not valid, ie that it is not true that 90% of the Z:TP owners also own SMG.
