Consider the paradox of birthdays. What would you estimate to be the probability that, in any group of 24 persons, two or more were born on the same day of the same month? Offhand you would say it will be very low. In fact, the probability is 27/50, or better than one half! In other words, if you were to bet even money on there being at least one coincidence of birthdays in a random collection of 24 persons, you would have a better than even chance of winning—over the long run.