7th Grade Statistics and Probability

Sampling

Probability I

Pobability II

100

Which of the following is a random sample of students at your school?

a. 10 girls

b. 10 of your friends

c. 10 people you know

d. 10 names picked from a hat

100

Which of the following events has the greatest theoretical probability?

a. Tossing a 5 on the number cube labeled 1-6.

b. tossing a penny and having it land tails up.

c. Spinning a 7 on a spinner with 5 sections labeled 2, 4 , 6, 8, and 10.

d. Pulling a green ribbon randomly from a bag with 1 red, 1 yellow, and 3 green ribbons.

100

Delcon spins a spinner two times with the number 1-4 on it. How many outcomes are possible?

a. 4

b. 8

c. 12

d. 16

200

Which of the following is a biased sample of the houses in you neighborhood?

a. 20 houses randomly from a complete directory

b. 20 houses generated randomly by a computer program

c. 20 houses randomly selected that have newspapers delivered

d. 20 houses randomly selected from a map of the neighborhood

b. 20 houses generated randomly by a computer program

200

A spinner has three equal sections. The following tables gives the results of 60 spins on the spinner.

outcome frequency

blues 25

red 18

yellow 17

How much greater is the experimental probability of landing on blue than the theorectical probability of landing on blue?

a. 1/4

b. 1/10

c. 1/12

d. 1/20

c. 1/12

200

Delcon spins a spinner two times with the number 1-4 on it.

What is the probability of landing on the number 1 with the first spin and 2 with the second spin?

a. 1/16

b. 1/12

c. 1/8

d. 1/4

a. 1/16

300

Some students are taking surveys to find out if people will vote to fund the building of a new city park on election day. Which student is taking the most representative sample?

a. Levonia asks 20 parents of her friends.

b. Quenton asks every other person leaving the library until he has asked 20 people.

c. Ruth calls 20 randomly selected registered voters.

d. Vince sends e-mails to 20 friends.

c. Ruth calls 20 randomly selected registered voters.

300

The following outcomes gives the results of tossing a number cube 50 times.

2 5 3 6 5 4 6 6 3 1

4 2 2 4 1 6 5 3 3 6

5 3 2 5 4 6 6 1 3 5

3 1 4 4 3 1 2 5 5 2

6 4 1 3 3 2 1 1 3 6

Which of the following is the experimental probability of tossing a 3 expressed as a percent?

a. 11%

b. 17%

C. 20%

d. 22%

c. 20%

300

Destiny has a bag with 3 green, 4 red, and 5 blue marbles. Destiny will pick 2 marbles form the bag, one at a time without looking. She will not replace a marble before picking the next marble. What is the probability of Destiny picking a red marble, followed by a green marble?

a. 1/12

b. 1/11

c. 7/12

d. 1/2

b. 1/11

400

A random sample is taken of people who have bought tickets for a concert in the sample, 13 out of 150 say they will contribute $5.00 toward a music scholarship for a local high school student. If 3, 500 people come to the concert, approximately how much money will be raised for the scholarship?

a. about $300

b. about $700

c. about $1, 300

d. about $1, 500

a. about $300

400

Mr. Perez designs a probability model to help him predict which color car high customers will want to buy. He puts equal numbers of red, black, white, gray, and blue slips of paper into a bag to represent all the different possible car colors. Which of the following statements about the model are true?

a. Mr. Perez will most likely not pull any black slips.

b. Mr. Perez is more likely to pull a red slip than a blue slip.

c. Adding another white slip would make this a non-uniform probability model.

d. The results of Mr. Perez's experiment are likely to exactly match the frequency with which his customers select each color car.

a. Mr. Perez will most likely not pull any black slips.

400

A bag hold a number of ribbons as given in the table below.

color number of ribbons in bag

black 1

blue 3

green 4

Jolene pulls a colored ribbon from a bag and does not replace it. She then draws a second ribbon.

How man outcomes are possible?

a. 5

b. 6

c. 8

d. 9

b. 6

500

Parents of students at a middle school were randomly selected to participate in a survey. Forty-two out of 60 parents who were surveyed support a proposal to buy new computers. There are a total of 456 parents with students at the middle school. Which is the best estimate of the number of those parents likely to support the new proposal?

a. 182

b. 319

c. 365

d. 438

b. 319

500

For each situation, tell whether the situation is unlikely, likely, or neither likely nor unlikely.

a. Drawing a 10 from a bag with 100 slips of paper numbered 1-100.

b. Rolling a number less than 5 on a number cube labeled with the numbers 1-6.

c. Drawing a red marble from a bag containing 8 red and 8 blue marbles.

a. unlikely

b. likely

c. neither likely nor unlikely

500

A bag hold a number of ribbons as given in the table below.

color number of ribbons in bag

black 1

blue 3

green 4

Jolene pulls a colored ribbon from a bag and does not replace it. She then draws a second ribbon.

What is the probability that Jolene draws two blue ribbons?

a. 3/28

b. 9/64

c. 9/56

d. 6/25

a. 3/28