I have been trying to use probability in real life occurrence like this whenever I can, so let's get started back of the envelop style according to this site h

I have been trying to use probability in real life occurrence like this whenever I can, so let's get started back of the envelop style according to this site http://research.collegeboard.org/content/sat-data-tables http://research.collegeboard.org/content/sat-data-tables Roughly 1.53 million students take up SAT every year and of which 10k students get perfect SAT score in Math (let's just focus on math for now) so that's 0.67% (rounded) people getting a perfect score out of the total. According to this data set, http://blog.rjmetrics.com/surprising-hacker-news-data-analysis/ http://blog.rjmetrics.com/surprising-hacker-news-data-analys... It says there are roughly 31k active users on HN, considering that I have personally seen many google employee's responding to a query/commenting on HN, let's assume a higher number of 2.5k. so, 2.5k * 0.0067 which is about 17 people, so there are 17 active google employees on HN which have perfect SAT score in Math. So that was my attempt, can someone provide a better probabilistic model? (maybe I will learn something new and exciting)