Probability Test Review

In a classroom of 20 students, 3 girls are named Stephanie. What is the probability that a student picked at random is named Stephanie?

• 3 out of 20

• 2 out of 20

• 5 out of 20

• 1 out of 20

A teacher randomly selects students to write the date on the board each day. There are 12 boys and 9 girls in the class. What is the probability that the teacher chooses a girl to write the date on the board?

• 3/7

• 9/20

• 12/21

• 12/20

Place the correct fraction to complete the sentence. A biologist is studying a group of alligators in a swamp and tagged 4 hatchlings, 5 juveniles, and 6 adults. The probability that an alligator captured at random in this area is a juvenile or hatchling is:

• 1/3

• 4/15

• 3/5

• 2/3

On a fair circular spinner, 20% of the circle is red, 1/2 of the circle is blue, and the rest of the circle is yellow. What is the probability that the outcome of one random spin is yellow?

• 30%

• 50%

• 70%

• 80%

Caroline recorded whether the answer to each flash card she uses for practice is a multiple of 10. Then she recorded the results in this chart.

What is the probability that one flash card chosen at random will have an answer that is a multiple of 10?

• 2/3

• 2/5

• 1/3

• 3/5

A student rolled a die 40 times during a game and used tally marks to record the result of each roll.

Which table shows the experimental probabilities of rolling a 4 and a 6, calculated separately?

• Outcome 4: 1/10, Outcome 6: 3/20

• Outcome 4: 1/8, Outcome 6: 1/3

• Outcome 4: 7/40, Outcome 6: 9/40

• Outcome 4: 1/5, Outcome 6: 1/8

What is the probability that a randomly selected student walks to school?

A group of 7th-grade students were asked whether they would like to be part of an after-school program. The table shows the results of the survey. Use the results to find the experimental probability of each response. Results of Survey: Yes (10), No (4), Maybe (6)

• 1/10, 1/5, 3/10

• 1/2, 1/5, 3/10

• 1/2, 1/5, 2/3

• 1/3, 1/2, 2/5

Wade has a spinner with 5 equal sections labeled Blue, Green, Orange, Red, and Pink. He spun the arrow on the spinner 25 times, and it landed on Pink 15 times. He will spin the arrow on the spinner an additional 2,000 times. Wade expects the experimental probability of the arrow landing on Pink to -

• Decrease to 60%

• Increase to 20%

• Decrease to 20%

• Increase to 60%

A fair coin is flipped 5 times, resulting in 5 tails. The coin is then flipped an additional 495 times, and tails result 240 more times. How does the experimental probability of getting tails change as the number of trials increases?

• The experimental probability gets closer to the theoretical probability of 0.5.

• The experimental probability would not change and would stay exactly at 1.

• The experimental probability decreases steadily to zero.

• The experimental probability stays exactly the same as in the first 5 flips.