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Ask HN: The Birthday Problem
What's the probability of two people sharing the exact birthday? (dd-mm-yyyy)
- pwg 7y ago1) Open browser 2) Navigate to https://duckduckgo.com/ https://duckduckgo.com/ 3) Type in "!w birthday problem" (without the quotes) 4) Read the wikipedia page that appears
- ryanthedev 7y agoThanks! I scoured the wiki. Didn't find any examples of using an infinite set. Could you be a bit more specific? It's definitely possible I missed the section.
- wallflower 7y agoIt is similar to the problem of grocery checkout. If there are n checkout lines, the probability of being in the quickest line is 1/n, assuming that all checkouts have lines. It is probably 1/(how many possible birthdays in a given year range). To be conservative (90 years): 1/90*365 or 0.003%.
- ryanthedev 7y agoIs 90 years the representation of the average age of a person? What if it didn't matter that they were alive or dead? Meaning I have a hat with every name and birthday of every "human". Every time someone is born, their name is added to the hat. Essentially an infinite set of names would be added. What's the probability when N is infinite? Like a grocery store with an infinite amount of checkout lines.