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

A fair coin is flipped 80 times and lands on heads 35 times.  What is the experimental probability of landing on TAILS?

What is 9/16 or 56.25%?

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. How does the theoretical probability of rolling a 3 compare to the experimental probability of rolling a 3, if you rolled a 3 seven times?

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

What is the probability of rolling three 4's in a row on a number cube?

1/216

Released STAAR Part 1

100

A bag contains colored tiles.  3 of the tiles are red, 6 of the tiles are green, and 3 of the tiles are blue.

A tile will be randomly selected from the bag.  What is the probability that the selected tile will be green?

What is 1/2 or 50%?

200

Nerissa has 5 pink bows, 1 blue bow, and 4 purple bows in a box.  She will randomly choose 1 bow from the box.

What is the probability that Nerissa will choose a purple bow?

What is 2/5 or 40%?

300

A bag contains flavored lollipops.  A lollipop will be randomly selected from the bag.  The bag contains 17 grape flavored lollipops, 8 cherry flavored, 14 watermelon flavored, and 16 strawberry flavored.

What is the probability that the selected lollipop will be either cherry or watermelon flavored?

What is 2/5 or 40%?

400

Four different kinds of juice were sold at lunch on Monday.  11 apple, 7 cranberry, 18 orange, and 4 pineapple juices were sold.

Assuming George bought a juice, what is the probability that he bought a pineapple juice?

What is 1/10 or 10%?

500

A student has a set of cards.  Each card has a picture of one geometric shape.  There are 8 cards with circles, 12 cards with pentagons, 10 cards with rectangles, 6 cards with squares, and 4 cards with triangles.

If the student chooses one card, what is the probability that the student will pick a card with more than 3 sides?

What is 7/10 or 70%?

Released STAAR Part 2

100

A survey showed that 8 out of 20 homeowners in a neighborhood had cable television.  If there were 320 homeowners in the neighborhood, how many could be expected to have cable television?

What is 128?

200

A teacher has a container of paper clips.  It has 8 pink paper clips, 14 purple paper clips, 12 yellow paper clips, and 16 blue paper clips.  What is the probability of NOT selecting a purple paper clip?

What is 18/25 or 72%?

300

Justin has 50 pictures in a photo album.  Of these pictures, 30 show his friends, 12 show his family, and 8 are selfies of Justin.  Justin is in 1/2 of the pictures with his friends and 1/2 of the pictures with his family.

What is the probability of randomly selecting a picture with Justin in it?

What is 29/50 or 58%?

400

A spinner is split into six equal sections numbered 1, 2, 3, 4, 5, and 6.  What is the probability of spinning a number greater than 4?

What is 1/3 or 33.3%?

500

Regina has three number cubes. The faces of each number cube are numbered from 1 to 6.  Regina will roll each number cube one time.

What is the probability that all three number cubes will land on an odd number?

What is 1/8 or 12.5%?