Fun with Birthdays

摘要

During your schooldays, did you ever wonder whether anyone else in the school had the same birthday as you? Did you notice that there were often two pupils with the same birthday in classes of 20 or so? Did you ever hear that the odds of that occurring are even in classes of only 23? In much smaller classes, did you notice that there were often two pupils with birthdays only a few days apart? Post-school, these remain as intriguing observations for all but the mathematically inclined, who may choose to pursue their statistical explanations.