Intro to Probability

What is probability?

• Represented as a fraction.

• The chance of an event happening.

• Favorable Outcomes/ Total Possible Outcomes

• All of the above

What is a Complement in probability?

• Saying-- You look very nice today.

• Probability of an event happening

• Probability of an event NOT happening

• Not here

What is the complement of choosing a red marble if there are 8 red marbles in a jar of 15?

• P' = 3/15

• P' = 7/15

• P' = 8/15

• P' = 15/8

How likely are you to roll a 1 on a regular die?

• P = 2/6

• P = 3/6

• P = 5/6

• P = 1/6

• F

• G

• H

• J

Billy Bob is rolling a number cube with the numbers 1-6. What is the probability that she will roll a 4 or a 5?

• ¹/2

• ¹/3

• ¹/6

• ¹/4

• 1/4, because the probability of renting a drama is 3/4.

• 3/4, because the probability of renting a drama is 1/4.

• 4/5, because the probability of renting a drama is 1/5.

• 1/5, because the probability of renting a drama is 4/5.

How likely are you to choose a yellow marble out of a jar, if there are 6 blue, 2 red, and 4 yellow?

• P = 4/10

• P = 1/3

• P = 2/12

• P = 6/12

How likely are you to NOT roll a 1 on a regular die? (Complement)

• P' = 2/6

• P' = 3/6

• P' = 5/6

• P' = 1/6

Cleo is making a model of the 9 planets in the solar system, and she needs Mars and Pluto. The clerk at the hobby shop draws a planet at random from a bin that has one of each planet in the solar system. What is the probability that he will NOT draw one of the two planets Cleo needs?

• 1/9

• 2/9

• 2/3

• 7/9