7th Grade Probability

Theoretical

100

Maria is flipping a coin and spinning a spinner. The spinner has 4 equal sections labeled A-D. What is the probability the coin will land on heads and the spinner will land on the letter "A"?

1/8 or 0.125, or 12.5%

200

The classic wood carousel at Carousel Park in Hampton, VA has 32 jumping horses and 16 standing horses. What is the probability of randomly selecting a jumping horse?

1/2, or 0.50, or 50%

300

What is the probability of rolling two odd numbers in a row with a standard number cube?

1/4, or 0.25, or 25%

400

There are 3 red marbles, 2 green marbles, and 1 yellow marble in a box. One marble is taken out and not replaces. A second marble is then taken out and not replaced. What is the probability both marbles that were taken out are red?

1/5, or 0.20, or 20%

500

Jarvonya spins a spinner with 5 equal sections numbered 1-5 and she spins another spinner with 5 equal sections with the letters A-E. What is the probability she will spin a 4 and a B?

1/25 or 0.04, or 4%

Experimental

100

Hasaan has a spinner with 5 equal sections, each a different color. After only 10 spins, the pointer had landed on red 40% of the time. After a whopping 1,000 spins, the pointer landed on red only 22% of the time. How can Hasaan account for this change in experimental probability?

As the number of trials increase, the experimental probability reaches closer to the theoretical probability. (The Law of Large Numbers)

200

It has rained on the last 2 out of 10 Fourth of July parades in Swanton.

What is the experimental probability that it will not rain on the Fourth of July parade this year?

4/5

300

A letter tile is randomly selected from a bag, recorded, and replaced 100 times. The results are listed below. What is the experimental probability of selecting the letter "E"? A = 16 E = 11 I = 29 O = 19 U = 25

11/100 or 0.11, or 11%

400

Pedro recorded the types of birds that visit his bird feeder. Based on the results below, what is the probability the next bird will be a chickadee? Woodpecker = 3 Chickadee = 5 Cardinal = 1 Sparrow = 13 Blue Jay = 3

1/5, or 0.20, or 20%

500

A six-sided die is thrown 50 times. Using the list below, how does the theoretical probability of rolling a 3 compare to the experimental probability of rolling a 3? Number on Die How Many Times it Landed on that Number 1 8 2 6 3 7 4 12 5 10 6 7

The theoretical probability is higher than the experimental probability. (Theoretical = 17%, Experimental = 14%)

Counting Principle

100

You are trying to decide what to wear to school. You know you have a green pair of pants, a red pair, and a blue pair. You also have a brown shirt, a plaid shirt, and a yellow shirt. How many different outfit combinations can you make?

9

200

What is the number of possible outcomes for spinning one spinner with 8 equal sections and another spinner with 6 equal sections?

48 possible outcomes

300

Amiya and Keyshawn are candidates for class president of the 7th grade. Ajaye, Chishon, and Laura are candidates for vice president. How many winning combinations are possible?

6

400

Ms. French is packing for a trip. She packs a white blouse, a pink blouse, a blue blouse, and a green blouse. She also packs a black suit, a navy blue suit, and a gray suit. What is the probability that the first outfit she wears is the gray suit with a pink blouse?

1 out of 12

500

There are 2 marbles and 3 cubes in a board game. The marbles are pink and green. The cubes are numbered 1, 2, and 3. A player randomly selects one marble and one cube. Make a tree diagram of all the possible outcomes?

Number 1- pink

Number 1-Green 

Number 2- pink

Number 2-Green 

Number 3- pink

Number 3-Green 

Vocabulary

100

It is the probability of what should occur.

Define "theoretical probability."

200

The probability of what actually occurs.

Define "experimental probability."

300

All the possible outcomes of an experiment. 

Sample Space

400

Define "independent event."

When one event occurs and the item is replaced before the second event occurs.

500

Define "dependent event."

When one event occurs and that item is not replaced before the second event occurs.

Random

100

How likely is it that a coin is flipped and lands on tails?

Equally likely

200

How likely is it that a number cube is tossed and lands on 3?

Unlikely

300

How likely is it that a number cube is tossed and it lands on 8?

never going to happen

400

Find the probability of choosing a green marble at random from a bag containing 5 green and 10 white marbles and then flipping a coin and getting tails.

The probability of choosing a green marble and a coin landing on tails is 1/ 6.

500

Alice was dealt a hand of cards consisting of 4 black and 3 red cards. Without seeing the cards, what is the probability that the first card will be black and the second card will be red?

The probability of Alice selecting a black card and then choosing a red card is  4/7.