Then we're not comparing the same thing. You said that the group's average should be weighted... and indeed that can be an approach - which would change the estimated factor of bias - but it wouldn't change the t test results - which confirm that there is a statistically significant difference between the two groups being compared.

By weighing the group's average, you don't change any individual ethnic group's results. If you look at these results (in the last graph provided in the diary), you'll see that in the Bosnian war, it appears that all ethnic groups are treated equally. However, these figures work on the wrong assumption that there was no killing of Croats by Muslims and vice-versa...

Compared to Muslims & Croats in Bosnia we have:
> a bias of 100:135 against Serbs in Croatia
> a bias of 100:179 against Serbs in Kosovo
> a bias of 22:100 in favour of Albanians
> a bias of 0:100 in favour of Croatian Croats