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

Hank 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 Hank 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

Leo tosses a coin 25 times and observes that it landed on heads 10 times. What is the experimental probability of landing on heads?

2/5

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

Pete 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 60 times. Using the list below, how does the theoretical probability of rolling a 3 compare to the experimental probability of rolling a 3? Experiment: rolled a 1-11 times, rolled a 2-6 times, rolled a 3-8 times, rolled a 4-14 times, rolled a 5-9 times, rolled a 6-12 times.

The theoretical probability is higher than the experimental probability. (Theoretical = 1/6, Experimental = 2/15)

Independent

100

A coin is flipped three times. What is the probability of getting all heads?

1/8

200

You roll a 1-6 number cube twice. What is the probability that you roll a 3 on the first roll and a 6 on the second roll?

1/36

300

A set of eight cards is labeled with the numbers 1 through 8. A card is chosen, replaced, and a second card is chosen. What is the probability that both cards will be even numbers?

1/4

400

A cooler contains 5 cans of diet cola, 6 cans of regular cola, and 4 cans of grape soda.

Janice randomly selects a can from the cooler. Then David randomly selects a can from the cooler. What is the probability that both Janice and David will select diet cola

1/9

500

Ms. Smith is picking cards from a deck. What is the probability that she picks 3 aces in a row if she replaces the cards?

1/2197

Dependent

100

Ms. Stanley has a bag of 15 marbles. 3 are blue, 6 are red, and 6 are yellow. What is the probability that she picks a yellow and then a red if she does not replace the marbles?

6/35

200

Bob has a set of 10 colored markers in a backpack. One is yellow and one is blue. What is the probability Bob will reach into the backpack without looking and grab the yellow marker and then reach in a second time and grab the blue marker?

1/90

300

A school cafeteria has 3 containers of white milk, 5 containers of chocolate milk and 2 containers of apple juice left. Jen is first in line and Jill is second. If the drinks are given out randomly, what is the probability that Jen will get chocolate milk and Jill will get apple juice?

1/9

400

A birthday party has a grab bag for each of the guests. There are 8 bags filled with candy, 5 containing CDs, and 2 grand prize bags with gift certificates. The bags are identically wrapped and shuffled. Joe is first to choose a bag, and Devon is second. What is the probability that Joe and Devon will both choose grand prize bags?

1/105

500

Mr. Watts is picking cards from a deck. What is the probability that he picks three aces in a row if he does not replace the cards?

1/5525

How Likely is it?

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?

impossible

400

How likely is it that a number cube is tossed and lands on any number 1-6?

Certain

500

How likely is it that a number cube lands on 2 and a coin lands on heads?

unlikely