Introductory Statistics Lesson 3.4 B Objective: SSBAT determine the number of combinations. Standards: M11.E.3.2.1

Combination  Arrangement of objects where order is NOT important  ABC is the same as BCA  Example: choosing a committee of 3 people

Combination vs. Permutation 1.Choosing 3 people from a group of 10 people 1.Choosing a President, Vice President, and Secretary from a group of 10 people 2.The number of ways to choose 5 books out of 7 to read to a class 2.The number of different orders you can read 5 books out of 7 books 3.The number of ways to choose 4 homerooms out of 20 to participate in a survey. 3.The number of different 4 digit access codes you can create (no number can repeat)

Combinations of n objects taken r at a time n = total objects r = the number you are choosing

Examples C 5 = 2, C 5 = 53,130

Examples C 28 = 1  Show how to do it in the calculator.

4.Simplify the following. 5C25C2 8C48C4 Answer:

5.Which is greater? 7 P 2 or 7 C 2  7 P 2 = 42 7 C 2 = 21 Answer: 7 P 2

Examples. 6.A state's department of transportation plans to develop a new section of interstate highway and receives 16 bids for the project. The state plans to hire four of the bidding companies. How many different combinations of four companies can be selected from the 16 bidding companies? 16 C 4 = 1,820

7.The manager of an accounting department wants to form a three-person advisory committee from the 20 employees in the department. In how many ways can the manager form this committee? 20 C 3 = 1,140

8. You want to buy five CDs from a selection of 10 CDs. How many ways can you make your selection? 10 C 5 = 252

Complete Worksheet 3.4B