8 notes basic counting rule permutations combinations

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Unformatted text preview: ting Rule; Permutations; Combinations Ordered partition Definition An ordered partition of m objects into k distinct groups of sizes m1 , m2 , · · · , mk is any division of the m objects into a combination of m1 objects constituting the first group, m2 objects comprising the second group, etc. The number of such partitions that can be made is denoted by m m1 ,m2 ,··· ,mk Remark: We called Notes Basic Counting Rules Permutations Combinations m m1 ,m2 ,··· ,mk the multinomial coefficient where m m1 , m2 , · · · , mk = m! m1 ! × · · · mk ! 4.9 Example 13 Basic Counting Rule; Permutations; Combinations 3 people get into an elevator and choose to get off at one of the 10 remaining floors. Find the following probabilities: 1 P(they all get off on different floors) 2 P(they all get off on the 5th floor) Basic Counting Rules 3 P(they all get off on the same floor) Permutations 4 P(exactly one of them gets off on the 5th floor) Combinations 5 P(at least one of them gets off on the 5th floo...
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This note was uploaded on 01/24/2014 for the course STAT 225 taught by Professor Martin during the Spring '08 term at Purdue University-West Lafayette.

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