Probability

Simple Probability

100

You flip a quarter. What is the probability of landing on tails?

1/2 or 0.5 or 50%

200

A spinner has equal sections numbered 1-6. What is the probability of spinning a 3?

1/6 or 0.1666... or 16.7%

300

Tim's book collection contains 10 books, including 5 biographies. 

If Tim randomly selects a book to read, what is the probability that it will be a biography?

1/2 or 0.5 or 50%

400

A grocery store has 4 raspberry yogurts, 6 strawberry yogurts, and 2 vanilla yogurts.

If you pick a yogurt at random, what is the probability of getting raspberry?

1/3 or 0.333... or 33%

500

A bag of jolly ranchers has 7 apple, 8 blue raspberry, 10 grape, and 5 cherry.

If you pick at random, what is the probability of getting cherry?

1/6 or 0.166... or 16.7%

Compound Probability

100

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

1/4, or 0.25, or 25%

200

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%

300

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 first and then selecting a standing horse?

2/9 or 0.22... or 22.2%

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%

Vocabulary

100

What percent is "certain" on the probability scale?

100%

200

What percent is "impossible" on the probability scale?

0%

300

What percent is "equally likely"?

50%

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.

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?

never going to happen

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