Probability

Probability

prepared by

Mr. Air Jaworski G. Obligar

Learning Outcomes

• define probability and other related important terms

• identify outcomes and types of events

• use probability to express the chance of an event occurring

• apply probability in real life scenarios

What is Probability

• Probability is how likely something is to happen. You might also hear it called chance.

• Probability can be expressed as fractions, decimals or percentages, or on a probability scale.

Probability Scales

• Certain - if an event will always happen.

• Most Likely - if an event has a good chance of happening.

• Even Chance - if an event has an equally likely of happening.

• Less Likely - if an event has a poor chance of happening

• Impossible - if an event will never happen or has no chance of happening

Identifying the outcomes

Event A: The sun will rise from east everyday.

Event B: Your friend will win the lottery today with one ticket.

Event C: You obtain a "tail" when you toss a coin.

Event D: It will snow in Quezon City at least once a year.

Event E: You will not get "1" when you roll a die.

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Multiple Choice

Anaiah has a spinner. (Refer to the image)

What is her chance of getting an odd number?

• Certain

• Most Likely

• Even Chance

• Less Likely

• Impossible

Multiple Choice

Argo has a deck of cards.

What is the probability that he will pick a number card?

• Certain

• Most Likely

• Even Chance

• Less Likely

• Impossible

Multiple Choice

There are marbles hidden in a bag. (Refer to the image)

Aidan pulls out one marble without looking.

Which kind of marble is Aidan most likely to pull out?

• Striped

• Spotty

• Grey

• White

Theoretical Probability

Can you tell me?

1.) What is the probability of rolling a 4 with a die?

2.) A bag contains 7 buttons. Three of them are green. What is the probability of picking a green button from the bag?

3.) A box contains 3 red and 5 blue marbles. What is the probability of picking a blue?

Multiple Choice

A box contains 2 red balls and 5 blue balls. Aura picks one ball from the box without looking.

What is the probability that Aura will pick a red ball?

• $$\frac{2}{7}$$

• $$\frac{5}{7}$$

• $$\frac{1}{7}$$

• $$\frac{2}{5}$$

Multiple Choice

Airel rolls a die.
What is the probability that Airel rolls an even number?

• $$\frac{3}{3}$$

• $$\frac{1}{2}$$

• $$\frac{4}{6}$$

• $$\frac{1}{3}$$

Let's try this!

In a class of 40 students, there are 24 boys and 16 of them are not short-sighted. Four of the girls are short-sighted. If a student is chosen at random, find the percent of the probability that the student is

(a) a girl

(b) not short-sighted

Multiple Choice

A box contains 50 marbles of which 8 are yellow, 10 are green, 16 are red and the remaining are blue.

A marble is drawn from the box at random. Find the percent of the probability that the marble drawn is green.

• 16%

• 20%

• 32%

• 10%

Multiple Choice

A box contains 50 marbles of which 8 are yellow, 10 are green, 16 are red and the remaining are blue.

A marble is drawn from the box at random. Find the percent of the probability that the marble drawn is blue.

• 16%

• 20%

• 32%

• 10%

Multiple Choice

A box contains 50 marbles of which 8 are yellow, 10 are green, 16 are red and the remaining are blue.

A marble is drawn from the box at random. Find the percent of the probability that the marble drawn is not orange.

• 0%

• 16%

• 32%

• 100%

Group Activity

A single card is drawn from a 52- standard deck of cards. Find the probability of getting a card that is: 

(a) a diamond

(b) a heart picture card

(c) not a joker

(d) a club King or a heart Jack

(e) NOT a black “five”

Do you have any questions?

That's all for today.

Thanks!