Transcript Probability
11.2 Probability Day 1 5/3/16 Tuesday Warm – up #2 5/3/16 Work on Extra W-S Counting Principle. (one sided) I will stamp Friday 4/29, when finished. Yesterday: Notes Pg. 3-4 Today: Notes Pg. 5-7 Homework Log Tues 5/3 Lesson 11 – 2 Learning Objective: To use permutations & combinations to count possibilities Hw: W-S 15-9 (both sides) Pg. 5-7 Notes packet 5/3/16 Lesson 11-2 Probability Day 1 Algebra II Pg. 5 Notes packet Probability # of favorable outcomes P(Event) = P(E) # of total outcomes “Probability of an event” Toss of coin: Probability of landing on heads: 1 P(H) = 2 Pg. 5 Notes packet Probability P(will definitely occur) = 1 ex: Have 1 die. P(roll a #) = 1 P(never occur) = 0 ex: Have 1 die. P(roll a letter) = 0 Pg. 5 Notes packet Ex: EX: A die is rolled. Find the probability the number showing is even. Even: 2, 4 , 6 # of favorable outcomes = 3 # of total outcomes = 6 3 1 P(Even) = 6 2 EX: A die is rolled. Find the probability the number showing is a 5 or a 6. 2 1 # of favorable outcomes = 2 P(5 or 6) = 6 3 Pg. 6 Notes packet Probability EX: A spinner is divided into tenths. The sections are numbered 1 to 10. If the spinner is spun, find the probability the number is a) 10 1 2 a multiple of 4 4 or 8 2 1 P(4 or 8) = 10 b) 5 between 0 and 30 1, 2, 3, 4, 5, …10 10 1 P(1, 2, … , 10) = 10 9 8 3 4 7 6 5 Pg. 6 Notes packet Probability A spinner is divided into tenths. The sections are numbered 1 to 10. If the spinner is spun, find the probability the number is c) d) 2 1 P(2) = 10 ½ ½ isn’t on the spinner P(½) = 0 0 10 10 1 2 9 8 3 4 7 6 5 Pg. 6 Notes packet Probability EX: A bag contains 8 brown socks and 6 black socks. If two socks are randomly drawn, what is the probability that they will match? Total socks = 14 Two cases: OR only 7 brown & 13 total left now 56 8 7 1. Two Brown: 14 13 182 30 6 5 2. Two Black: 14 13 182 only 5 black & 13 total left now 56 30 182 182 86 43 182 91 Pg. 6 Notes packet Probability EX: A die is rolled. Find the probability of each event. a) The number showing is less than 5 4 2 6 3 1, 2, 3, or 4 b) The number showing is between 2 and 6. 3, 4, 5 3 1 6 2 Pg. 6 Notes packet Probability EX: Two dice are rolled and the numbers are noted. Find the probability of each event. a) The sum of the numbers is less than 5 Pg. 7 Copy it down! Part a) Sum < 5 ? Possibilities when 2 dice are rolled TOTAL = 36 Pg. 6 Notes packet Probability Two dice are rolled and the numbers are noted. Find the probability of each event. a) The sum of the numbers is less than 5 6 1 36 6 b) The sum of the numbers is 4 or 5. Part b) Sum = 4 or 5 ? Possibilities when 2 dice are rolled Back to Pg. 6 Notes packet Probability Two dice are rolled and the numbers are noted. Find the probability of each event. b) The sum of the numbers is 4 or 5. P(4 or 5) = 7 36 Probability EX: There are 12 tulip bulbs in a package. Nine will yield yellow tulips and three will yield red tulips. If two bulbs are selected at random, find the probability of each event. a) Both tulips will be red only 2 red & 11 total left now b) 6 3 2 1 12 11 132 22 12 total 9 Yellow 3 Red One tulip will be yellow and the other red 9 12 3 R/Y 12 Case I: Y/R Case 2: 27 3 11 132 27 9 11 132 27 27 54 9 132 132 132 22 Homework 15-9 Probability WS