I met with some of my closest friends from college today because it was Homecoming. It got me all nostalgic, because I realized how difficult it is to just be physically near my friends after college. Although a lot of my friends are still in manhattan, many have moved to other cities. Even if they live in NYC, some people I see less frequently than others. I guess according to Bayes' rule, the probability that I meet friends given that they live in Manhattan is:

P(Meet Friend | Live in Manhattan) = P(Live in Manhattan | Meet Friend)*P(Meet Friend) / P(Live in Manhattan)


P(Live in Manhattan) = Number of friends living in Manhattan / Total number of friends

P(Meet Friend) = Number of friends I meet per month after college graduation / Total number of friends