SOLUTION: A web based test generator assigns 1 of 100 possible questions as the first question on a practice quiz. If 20 students take the quiz, what is the probability that at least 2 of th
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Question 366312: A web based test generator assigns 1 of 100 possible questions as the first question on a practice quiz. If 20 students take the quiz, what is the probability that at least 2 of the 20 are assigned the same first question? Answer by edjones(8007) (Show Source):
You can put this solution on YOUR website! 100/100 * 99/100 * 98*100 * ... * 81/100 = Probability that no-one is assigned the same question.
=100!/(80!*100^20)
=.13
1-.13=.87 the probability that at least 2 of the 20 are assigned the same first question.
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This question is similar to the birthday problem which states that if 23 people are in a room it is statistically likely that 2 have the same birthday.
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Ed
