01_Probability of Simple Events

8/10/2019 01_Probability of Simple Events

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Probabilityof SimpleEvents


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Probability of Simple Events

Objective:Students will be able to find the probability of a

simple event.

Students will be able to understand thedistinction between simple events andcompound events.

Essential Question:

(1) How do I find the probability of a simpleevent?

(2) How can I distinguish between a simple and

compound event?


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Vocabulary: Outcomeone possible result of a probability. Sample Spacethe list of possible outcomes

for a probability event. Randomoutcomes that occur at random ifeach outcome is equally likely to occur. Simple Eventa specific outcome or type of

outcome. Complementary Eventsthe events of one

outcome happening and that outcomes nothappening are complimentary; the sum of theprobabilities of complementary events is 1.


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Real World Example:Best Buy is having an IPOD giveaway.They put all the IPOD Shuffles in abag. Customers may choose an IPODwithout looking at the color. Inside thebag are 4 orange, 5 blue, 6 green, and5 pink IPODS. If Maria chooses one

IPOD at random, what is the probabilityshe will choose an orange IPOD?



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Real World Example:Best Buy is having an IPOD giveaway.They put all the IPOD Shuffles in abag. Customers may choose an IPODwithout looking at the color. Inside thebag are 4 orange, 5 blue, 6 green, and5 pink IPODS. If Maria chooses one

IPOD at random, what is the probabilityshe will choose an orange IPOD?

P(orange) = 4/20= 2/10= 1/5or 20%



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What is a PROBABILITY?

- Probability is the chance that some

event will happen

- It is the ratio of the number of

ways a certain event can occur tothe number of possible outcomes



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number of favorable outcomesnumber of possible outcomes

Examples that use Probability:(1) Dice, (2) Spinners, (3) Coins, (4) Deck ofCards, (5) Evens/Odds, (6) Alphabet, etc.


P(event) =


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0% 25% 50% 75% 100%

0 or .25 0r .5 or .75 1

Impossible Not Very Equally Likely Somewhat Certain

Likely Likely



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Example 1:Roll a dice.What is the probability of rolling a 4?

# favorable outcomes

# possible outcomes

16

The probability of rolling a 4 is 1 out of 6


P(event) =

P(rolling a 4) =


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Example 2:Roll a dice.What is the probability of rolling an even

number?


# possible outcomes

3 16 2

The probability of rolling an even number is 3 out of 6 or .5or 50%


P(event) =

P(even #) = =


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Example 3:Spinners.What is the probability of spinning green?


# possible outcomes

1 14 4

The probability of spinning green is 1 out of 4 or .25 or25%


P(event) =

P(green)= =


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Example 4:Flip a coin.What is the probability of flipping a tail?


# possible outcomes

1 12 2

The probability of spinning green is 1 out of 2 or .5 or 50%


P(event) =

P(tail)= =


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Example 5:Deck of Cards.What is the probability of picking a heart?

# favorable outcomes 13 1

# possible outcomes 52 4The probability of picking a heart is

1 out of 4 or .25 or 25%

What is the probability of picking a non heart?

# favorable outcomes 39 3

# possible outcomes 52 4

The probability of picking a heart is

3 out of 4 or .75 or 75%


P(heart) = = =

P(nonheart)= = =


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Key Concepts:

- Probability is the chance that someevent will happen

- It is the ratioof the number of

ways a certain even can occurtothe total number of possibleoutcomes



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Guided Practice: Calculate the probabilityof each independent event.

1) P(black) =

2) P(1) =

3) P(odd) =

4) P(prime) =



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Guided Practice: Answers.

1) P(black) = 4/82) P(1) = 1/

8

3) P(odd) = 1/2

4) P(prime) = 1/2



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Independent Practice: Calculate theprobability of each independent event.

1) P(red) =

2) P(2) =

3) P(not red) =

4) P(even) =



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Independent Practice: Answers.

1) P(red) = 1/2

2) P(2) = 1/4

3) P(not red) = 1/2

4) P(even) =1

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Real World Example:A computer company manufactures 2,500

computers each day. An average of 100 of

these computers are returned with defects.What is the probability that the computeryou purchased is notdefective?

P(not defective) = # not defective = 2,400 = 24

total # manufactured 2,500 25



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Homework:

- Workbook Practice 11-1


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01_Probability of Simple Events