Depending on who you ask: “A variety of studies suggest that 8–15% of world population are left-handed”, elsewhere on Wikipedia 10% is quoted, and 70-90% are right-handed. So the percentage of left-handed people overall is definitely less than that among MENSA members. Ergo a left handed person is extra-likely to end up in MENSA (and earns 10-15% higher wages, according to another Wikipedia entry). http://en.wikipedia.org/wiki/Left-handedness
http://en.wikipedia.org/wiki/Handedness P.S.: When they say 70-90%, they account for people being cross-dominantly handed (meaning you can do some things with the left and some with the right - which is how discounted by people just looking at what hand you write with etc) and people being ambidextrous (meaning you just rock with both).




