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3.4C-Combinations . Combinations of n objects taken r at a time Order does NOT matter nCr = n!/(n-r)!n! n=# objects r=# taken Calculator : n, MATH, → PRB, 3:nCr, r, ENTER
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3.4C-Combinations • Combinationsof n objects taken r at a time • Order does NOT matter • nCr = n!/(n-r)!n! n=# objects r=# taken • Calculator: n, MATH, → PRB, 3:nCr, r, ENTER • Ex: 16 construction companies are bidding to do the job. How many different combinations of 4 companies can be chosen? .
3.4C-Combinations • Combinationsof n objects taken r at a time • Order does NOT matter • nCr = n!/(n-r)!n! n=# objects r=# taken • Calculator: n, MATH, → PRB, 3:nCr, r, ENTER • Ex: 16 construction companies are bidding to do the job. How many different combinations of 4 companies can be chosen? no particular order .
3.4C-Combinations • Combinationsof n objects taken r at a time • Order does NOT matter • nCr = n!/(n-r)!n! n=# objects r=# taken • Calculator: n, MATH, → PRB, 3:nCr, r, ENTER • Ex: 16 construction companies are bidding to do the job. How many different combinations of 4 companies can be chosen? no particular order . ₁₆C₄ =
3.4C-Combinations • Combinationsof n objects taken r at a time • Order does NOT matter • nCr = n!/(n-r)!n! n=# objects r=# taken • Calculator: n, MATH, → PRB, 3:nCr, r, ENTER • Ex: 16 construction companies are bidding to do the job. How many different combinations of 4 companies can be chosen? no particular order . ₁₆C₄ = 16!/(16-4)!4!
3.4C-Combinations • Combinationsof n objects taken r at a time • Order does NOT matter • nCr = n!/(n-r)!n! n=# objects r=# taken • Calculator: n, MATH, → PRB, 3:nCr, r, ENTER • Ex: 16 construction companies are bidding to do the job. How many different combinations of 4 companies can be chosen? no particular order . ₁₆C₄ = 16!/(16-4)!4! = 16!/(12!4!)
3.4C-Combinations • Combinationsof n objects taken r at a time • Order does NOT matter • nCr = n!/(n-r)!n! n=# objects r=# taken • Calculator: n, MATH, → PRB, 3:nCr, r, ENTER • Ex: 16 construction companies are bidding to do the job. How many different combinations of 4 companies can be chosen? no particular order . ₁₆C₄ = 16!/(16-4)!4! = 16!/(12!4!)=1820
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? .
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? .
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? .
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = 16!/(16-3)!3! • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? .
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = 16!/(16-3)!3! = 16!/(13!3!) • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? .
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = 16!/(16-3)!3! = 16!/(13!3!) = 560 • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? .
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = 16!/(16-3)!3! = 16!/(13!3!) = 560 • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? order IS important (distinguishable permutation) .
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = 16!/(16-3)!3! = 16!/(13!3!) = 560 • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? order IS important (distinguishable permutation) . 11!/(1!4!4!2!)
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = 16!/(16-3)!3! = 16!/(13!3!) = 560 • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? order IS important (distinguishable permutation) . 11!/(1!4!4!2!) = 34650 possible & 1 favorable 1/34650
More Examples: • There are 16 employees. In how many ways can an advisory committee of 3 be chosen? order NOT important ₁₆C₃ = 16!/(16-3)!3! = 16!/(13!3!) = 560 • A word has 1 M, 4 I’s, 4 S’s & 2 P’s. What is the probability they can be arranged to spell MISSISSIPPI? order IS important (distinguishable permutation) . 11!/(1!4!4!2!) = 34650 possible & 1 favorable 1/34650 = .000029
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 = .0056 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 = .0056 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. Order NOT important .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 = .0056 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. Order NOT important P(desirable)/P(Total) .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 = .0056 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. Order NOT important P(desirable)/P(Total)=P(5 of 13 D)/P(5 of 52) .
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 = .0056 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. Order NOT important P(desirable)/P(Total)=P(5 of 13 D)/P(5 of 52) . ₁₃C₅/₅₂C₅
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 = .0056 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. Order NOT important P(desirable)/P(Total)=P(5 of 13 D)/P(5 of 52) . ₁₃C₅/₅₂C₅ = 1287/2598960
More Examples • A word has 1 L, 2 E’s, 2 T’s, & 1R. What is the probability they will be arranged to spell LETER? Order IS important Distinguishable permutation 6!/(1!2!2!1!) = 180 possible, 1 desirable = 1/180 = .0056 • Find the probability of being dealt 5 diamonds in a row from a standard deck of 52. Order NOT important P(desirable)/P(Total)=P(5 of 13 D)/P(5 of 52) . ₁₃C₅/₅₂C₅ = 1287/2598960 = .0005
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men?
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W)
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ =
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ = 10·1
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ = 10·1 =10 P(choose 3 from 12)
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ = 10·1 =10 P(choose 3 from 12) = ₁₂C₃ =
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ = 10·1 =10 P(choose 3 from 12) = ₁₂C₃ = 220
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ = 10·1 =10 P(choose 3 from 12) = ₁₂C₃ = 220 P(all men) = P(3 M)·P( 0 W) / P(3 from 12)
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ = 10·1 =10 P(choose 3 from 12) = ₁₂C₃ = 220 P(all men) = P(3 M)·P( 0 W) / P(3 from 12) 10/220 =
More Examples: • A group contains 5 men and 7 women. If 3 are selected at random, what is the probability that all 3 are men? Order is NOT important P(3 M)·P(0W) = ₅C₃· ₇C₀ = 10·1 =10 P(choose 3 from 12) = ₁₂C₃ = 220 P(all men) = P(3 M)·P( 0 W) / P(3 from 12) 10/220 = .045