Assuming half of the 13% were a combination of a 50-50 split. Half of his voters were male and half were female. That would be 6.5% Female and 6.5% male for a total of 13%.
You're thinking is a little off on this. Assuming that the entire number of votes was 50-50 male-female, and assuming that Newt got equal numbers of male and female, then the 13% that Newt got would represent 13% of all the males who voted and 13% of all the females who voted.
You seem to be saying that he got only 6.5% of all the females who voted (and only 6.5% of all the males who voted) and that's just not correct.
Ok. Lets say Newt got 100,000 votes which represent 13%
50,000 were female, 50,000 were male.
50,000 would be 6.5% of his total female vote,
50,000 would be 6.5% of his male vote.
I don’t see anything wrong with my math.