1. Fri 5/6 Lesson 11 – 4 Learning Objective: To use two way tables & tree diagrams to find probability Hw: 11 – 4 WS

2. Algebra II

3.  To use two way tables to find conditional probability  To use diagram tree to find conditional probability

4. Conditional Probability – The probability that an event B will occur given that event A has already occurred Contingency Table (Two Way Table) – frequency table that contains data from two different categories

5. 1. P(has diploma) 2. P(has diploma & experience) 3. P(has experience/has diploma) 4. P(no diploma/has experience) 81 9 5931 90

6. 5. P(male) 6. P(bachelors) 7. P(female/associate) 8. P(not associate/male) 678 1456 843 1291 2134

7. H =heavy snowfallL = light snowfall O = school openC = school closed 9. P(O) = H & O or L & O = (0.4)(0.2) + (0.6)(0.7) = 0.5

8. H =heavy snowfallL = light snowfall O = school openC = school closed 10. P(H & O) = (0.4)(0.2) = 0.08 11. P(H/C) = 0.64

9. H =heavy snowfallL = light snowfall O = school openC = school closed 12. P(L/O) = 0.84

10. H =heavy snowfallL = light snowfall O = school openC = school closed 13. P(L/C) = 0.36

11. H =heavy snowfallL = light snowfall O = school openC = school closed 14. P(H/O) = 0.16

12. 15. A football team has a 70% chance of winning when it doesn’t snow, but only a 40% chance of winning when it snows. Suppose there is 50% chance of snow. Make a tree diagram to find the probability that the team will win. NS S 0.5 W NW 0.7 0.3 W NW 0.4 0.6 P(win) = NS&W OR S&W (0.5)(0.7) + (0.5)(0.4) 0.55

13. 16. Survey, 17% male. Of the male respondents, 33% are left handed. Of the female respondents, 90% are right handed. Find P(respondent is both male & right handed). M F 0.17 0.83 R L 0.67 0.33 R L 0.9 0.1 P(M&R) = (0.17)(0.67) =11.39%

14. 17. Survey, 17% male. Of the male respondents, 33% are left handed. Of the female respondents, 90% are right handed. Find P(female respondent is left handed). M F 0.17 0.83 R L 0.67 0.33 R L 0.9 0.1 P(L/F) = 10%