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Explore ice cream preferences based on a survey and learn about basic probability concepts. Calculate probabilities of different outcomes and understand the concepts of independent and dependent events.
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Thursday 05/16 Warm Up 200 people were surveyed about ice cream preferences. 78 people said they prefer chocolate. 65 people said they prefer strawberry. The rest prefer vanilla. • What percentage of people prefer chocolate? • What percentage of people prefer vanilla?
Basic Probability Probability is the science or study of the chances of an event occuring.
Examples of probability in the real world Can you think of anymore?
The scale of probability Impossible- never could happen Unlikely- probably won’t happen Sometimes- maybe, equal chance More likely- probably will Certain- always, for sure!
Example: Determine the scale of probability of an event happening. • The spinner landing on green? • The spinner landing on yellow? • The spinner landing on blue? • The spinner landing on a color?
Sample Space A sample space is a set of all possible outcomes. What would be the sample space of… • A six sided die? • Flipping a coin? • Flipping three coins?
Examples If the wheel has all of your names, plus your teachers name, what is the probability your name will be selected?
Examples You have a basket of eggs with 4 pink eggs, 5 green eggs, 6 yellow eggs, and 2 blue eggs. What is the probability of pulling out a green egg? P(G) What is the probability of pulling out an egg that is not pink? P(notP) What is the probability of pulling out a blue egg? P(B)
Examples I have a six sided die. What is the probability I roll a 4? What is the probability I roll an even number? What is the probability I roll a number that is not 3?
Task 9.1 TB or Not TB? Find the following probabilities • A person has TB • A person does not have TB • A person has TB and tests positive • A person has TB and test negative • A person doesn’t have TB and test positive • A person doesn’t have TB and test negative
Friday 05/17 Warm Up Open your booklets to page 3. Answer questions #1-5 on your warm up sheet.
Experimental probability is the probability of something happening based off of actual experimental data.
Experiment Time! We are going to roll a die 15 times and record our data. Then find the following: • P(1) • P(5 or 6) • P(odd number) • P(even number) • P(a number divisible by 3)
Experiment Time! We’ve got a basket of 20 eggs. We will record our data. Then find the following: • P(green) • P(blue) • P(not pink) • P(blue or yellow)
Exit Ticket Complete the Two-Way Table
Monday 05/20 Warm Up Open your booklets to page 7. Answer questions #1-4 on your warm up sheet.
Events are independent events if the occurrence of one event does not affect the probability of the other.
Independent Events If A and B are independent events, then P(A and B)= P(A) • P(B)
Example 1 Find the probability of flipping a coin twice and it landing on Heads both times. **Is flipping a coin an independent event?** YES The outcome of one toss does not affect the probability of heads on the other toss There are two ways to solve this: Draw a tree diagram Answer with multiplication
Example 2 A six-sided cube is labeled with the numbers 1, 2, 2, 3, 3, and 3. Four sides are colored red, one side is white and one side is yellow. Find the probability. • Tossing 2, then 2 • Tossing red, then white, then yellow.
Events are dependent events if the occurrence of one event affects the probability of the other.
Dependent Events If A and B are dependent events, then P(A and B) = P(A) • P(B | A) Where P(A | B) is the probability of B, given that A has occurred.
Example 1 There are 2 lemons and 1 lime in a bag. If you pull out two pieces of fruit, the probability change depending on the outcome of the first. • P(2 lemons) • P(lime, then lemon)
Example 2 Two number cubes are rolled - one red, and one blue. Explain why the events are dependent. Then find the indicated probability. The red cube shows a 1, and the sum is less than 4.
You Try! Two cards are drawn from a deck of 52. Determine whether the events are independent or dependent. Find the probability. • Selecting two hearts when the first card is replaced • Selecting two hearts when the first card is not replaced • A queen is drawn, is not replaced, and then a king is drawn
Tuesday 05/21 Warm Up Open your booklets to page 14. Answers questions #1-5 on your warm up sheet
The conditional probability of an event B, in relation to event A, is the probability that event B will occur given the knowledge that an event A has already occurred
The probability is written P(B | A), notation for the probability of B given A
Conditional Probability We need to revisit our previous discussion of independent and dependent events.
Example Two colored dice (one white, one red) are rolled. • What is the probability of rolling “box cars” (two sixes)? • What is the probability of rolling “box cars” knowing the first toss is a six?
Conditional Probablity If events A and B are dependent (where A has effect on the probability of event B), then we saw that the probability that both events occur is defined by P(A and B) = P(A) • P(B | A)
Conditional Probablity Dividing both sides of this equation by P(A) gives us our formula for conditional probability of event B given event A, where event A affects the probability of event B:
Example A bag contains 12 red M&Ms, 12 blue M&Ms, and 12 green M&Ms. What is the probability of drawing two M&Ms of the same color in a row?
Example In a school of 1200 students, 250 are seniors, 150 students take math, and 40 students are seniors and are also taking math. What is the probability that a randomly chosen student who is a senior, is taking math?
Wednesday 05/22 Warm Up Open your booklets to page 18. Answer questions #1-8 on your warm up sheet.
Thursday 05/23 Warm Up Open your booklets to page 17. Answer questions #1, 2a and 2b on your warm up sheet.
Friday 05/24 Warm Up Open your booklets to page 29. Answer questions #13 - 15