Unit 6: Probability - Lesson 2

Unit 6: Probability

Lesson 2: Probability of Simple Events

Vocabulary

• Probability: The likelihood of an action or event happening during an experiment

• Favorable Outcomes: What we want to happen in an event

How to calculate probability

• Step 1: List out the Sample Space, and Determine the total number of outcomes

• Step 2: Determine the number of ways our Favorable outcome can occur

• Step 3: Create a Ratio with favorable over total

Multiple Choice

What is the probability of landing on heads if you toss a coin?

• 1/2

• 1/3

• 1/6

• 2/2

Multiple Choice

What is the probability of rolling a fair number cube and landing on "3"?

• 1/3

• 1/2

• 1/6

• 1/5

Probability Scale

• 0% = Impossible to happen

• 25% = Unlikely

• 50% = Even Change

• 75% = Likely

• 100% = Certain

Probability Scale Examples

• The likely hood of rolling a 0 on a number cube is 0% so it is impossible

• The likely hood of getting heads is 50%, so it has an even chance

• The likely hood of rolling a number >0 is 100% so it is certain

Multiple Choice

What is the Probability of rolling a 4 or P(4)?

• 1/4

• 1/5

• 1/6

• 1/2

Multiple Choice

What is the likely hood of rolling an even number or p(even)?

• 1/6; unlikely

• 0/6; impossible

• 6/6; certain

• 3/6; Evenly Likely

"OR" = addition

• Sometimes you will have probabilities asking for Event 1 or Event 2

• To solve these problems you will find the event probability for each

• Then ADD them!

Multiple Choice

What is the Probability of drawing a green or yellow marble? P(Green OR Yellow)=?

• 1/2

• 1/4

• 1/3

• 5/12

Multiple Choice

What is the Probability of drawing a Blue, or Red marble? P(Blue OR Red)=?

• 1/2

• 7/12

• 1/3

• 5/12

Complement Events

Are 2 events in which EITHER one or the other MUST happen, but they CANNOT happen at the same time.

How do you know if it is a complement problem?

• When it says: Not [event]

• Ex: What is the probability of Not rolling a number greater than 4?

• Ex: P(Not greater than 4)

Multiple Choice

What is the probability of Not spinning blue?

• P(Not Blue) = 1/4

• P(Not Blue) = 1/2

• P(Not Blue) = 2/3

• P(Not Blue) = 3/4

Multiple Choice

What is the probability of NOT rolling a Prime Number?

• 0/6

• 1/6

• 1/2

• 1/3

Let's Review

Multiple Choice

What is the probability of drawing D or P(D) = ?

• 1/4

• 1/9

• 1/5

• 1/3

Multiple Choice

What is the probability of drawing S, V, or L? P(S,V, or L) = ?

• 2/3

• 1/2

• 1/3

• 5/9

Multiple Choice

What is the probability of Not Drawing D? P(Not D) = ?

• 8/9

• 7/9

• 2/3

• 1/2

Poll

How do you feel about this concept?

• This concept scares me

• I feel good about this concept

• I am on the fence about this concept

• I feel like I will never get this concept

• Other