Math 7 CFA 8 Probability Review

Stacy uses a spinner with six equal sections numbered 1, 2, 3, 4, 5, and 6 to play a game. Stacy spins the pointer 120 times and records the results. The pointer lands 9 times on the section numbered 1, 24 times on 2, 18 times on 3, 21 times on 4, 20 times on 5, and 28 times on 6. A winning spin is a 2.

1. 1) Find the theoretical and experimental probabilities of winning

2. 2) Compare the probabilities. Which is greater?

3. Theoretical: P(2) = ​ (a)  

4. Experimental P(2) = ​ (b)  

5. The theoretical probability ​ (c)   the experimental probability.​

• is less than
• is greater than

Rachel plays a game by rolling two number cubes with sides numbered 1 through 6. The possible outcomes are shown in the table. To win the game, the sum of the numbers rolled must be 11. What is the probability that Rachel will win the game?

P(sum of 11) =

Stacy uses a spinner with six equal sections numbered 1, 2, 3, 4, 5, and 6 to play a game. Select all the true statements about this game.

• The probability of landing on an even-numbered section is 37.5%

• It is equally likely as not that you will land on an even number.

• It is certain that the pointer will land on a number less than 7.

• This spinner is fair.

• It is likely that the spinner will land on a number less than 3.

Answer explanation

The correct statements are: It is equally likely as not that you will land on an even number, It is certain that the pointer will land on a number less than 7, and This spinner is fair.

A spinner has 5 equal-sized sections. Two of the sections are green.

What is the theoretical probability the spinner will land on green?​ (a)  

Describe the probability of green in words:

The spinner is ​ (b)   to land on green

• unlikely
• likely

• as likely as not

• 40%
• 60%

• 50%

Answer explanation

The probability of landing on green is 2 out of 5, making it unlikely. This corresponds to a 40% chance of landing on green.

Match the percent of probability with the best way to describe it:

• Between 0% and 50%

• as likely as not

• 100%

• certain

• Between 50% and 100%

• likely

• 50%

• impossible

• 0%

• unlikely

The 25 members of the class will each draw a pencil from a box that contains 7 red, 8 blue, 6 yellow, and 4 green pencils. What is the probability that a class member draws a pencil that is NOT green?

Mr. Shelton has 6 students who have no missing assignments and are eligible for a chance to win a special prize. He assigns each of them a number from 1 to 6. He then places the following numbers in a hat: 1, 2, 2, 3, 4, 5, 6, 6. He chooses a number from the hat. Is this considered a mathematically fair way to pick a winner?

• This event is fair because each student has a chance of being chosen.

• This event is unfair because the probability of choosing each number is not the same.

• This event is unfair because every student should get a prize, including those who had missing assignments.

Answer explanation

This event is unfair because the probability of choosing each number is not the same.

Myron is comparing the probabilities of the two spinners shown. Select all the true statements.

• The right spinner is twice as likely to land on 1 as the left spinner.

• Both spinners are fair spinners.

• The probability of landing on 3 is greater on the left spinner than on the right spinner.

• The probability of landing on an even number is greater on the left spinner than on the right spinner.

Answer explanation

The correct statements are: The probability that the right spinner will land on 1 is 1/2. The probability of landing on 3 is greater on the left spinner. The probability of landing on an even number is greater on the left spinner.

Ben rolls a regular number cube with faces numbered 1 through 6. The probability of landing on a number less than 7 is ___%. Please don't type the percent sign in your answer or it will be counted wrong.

Jacob throws an 12-sided cube with faces numbered 1 through 12. Select all of the true statements.

• P(13) = 0

• This is a fair cube.

Answer explanation

The correct statements are: P(even number) = 1/2, P(13) = 0, P(number less than 5) = 1/3, and the cube is fair.