Birthday Problem Essay

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Most people are surprised by the “Birthday Problem.” (They underestimate the probability that 2 people in the room with share a birthday for a given number of people in the room or overestimate the number of people in the room needed so that 2 of them will share a birthday with a given probability.) Why do you think people’s intuition is wrong for this particular problem? Do you think people’s faulty intuition for this minor problem can tell you anything about systematic biases we should expect to see for important judgments? Select one important judgment that people have to make and explain why you believe the psychological underpinnings behind it are similar to those behind the birthday problem For finding two people in the room that were born the same day for a given number of people you need to fill at least 367 people in the same room. To obtain the probability to find two people with the same birthday you have to calculate 1 - (365 * 364 * … * (365-n))/ 365n , where “n” is equal to the number of people analyzed. For n=5, the probability that two of them share the same birthday will be around 3%. There is a small chance, but not impossible. Suppose that you ask this question to someone who works with a lot of people and meets at least 10 persons a day. For sure, he doesn’t take the time to ask each of them their birthdays. How will he suppose that more than one of the persons he met in the last weeks were born the same day (and probably year) as he was? In this case, the lack of information (or time) and/or the large number of people met are some of the main factors for underestimating this occurrence. The same happen whenever we cannot explain a surprising situation. Because so many things happened every day in our lives, we usually don’t take the time to analyze each of them. We stop only at those that really aware or surprise us. A very good
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