13.10 Independent and Dependent Events Objective: Students will be able to decide if events are dependent on each other and how to use that to find probability.

Information Independent event: first event doesn’t affect other events Ex: draw a card, replace and draw another Dependent events: one event affects other events Ex: draw a card, don’t replace, and draw another

Identify if the event is dependent or independent Toss coin lands heads, toss again lands tails Your roll a 5 on a die, then you roll a 6. You draw a marble from a bag, put it back and randomly draw another. Roll an odd number on a die, roll again and get even number You draw a spoon first and a fork second. You draw a jack, don’t replace, and draw another jack.

Probability of independent events 4-digit password. Each number can be used over. What’s the probability the first two digits are 1? What’s the probability that all four digits are 1?

Probability of independent events Marbles: 10 red, 8 blue, and 2 yellow. What’s the probability you draw a red, replace it, then draw a yellow? Marbles: 10 red, 8 blue, and 2 yellow. What’s the probability you draw a red, replace it, then draw a blue?

Probability of Dependent Events Choose a utensil from drawer: 12 spoons, 8 forks, and 6 knives. What’s probability you draw a spoon, don’t replace, then draw a fork? 4 blue socks, 6 gray socks, 8 black socks. Find probability choose 2 blue socks? Find probability choose 2 gray socks Find probability choose 2 black socks.

Probability of Dependent Events Weather forecaster says 25% rain today and 55% tomorrow. Tell if ind/dep. Find Prob. Event A: rains today Event B: rains tomorrow. Teacher assigns you, a friend, and 4 others to seats. Probability you get 1st seat and a friend gets 2nd seat?

Wrap-up Questions/Comments Ic: text pg. 793, #: 5-14 Hw: workbook 197