Random and Representative Sampling

The principal at Marina Middle School wants to determine if the 120 students in the seventh grade prefer to visit Catalina Island or Camp Mosaic for their end-of-year trip. Which of the following is a representative sample of the population? Select all that apply.

• 20 sixth-grade students, 20 seventh-grade students, and 20 eighth-grade students

• 10 seventh-grade boys and 10 seventh-grade girls

• 25 seventh-grade students

• 15 seventh-grade boys and 5 teachers

• 25 students from the school

Students in Mrs. Walsh’s math class wanted to know the favorite snacks of students in the school. How could they generate a random sample to survey?

• Line up the students by height and choose the first 20 students.

• Use the school roster and randomly choose 50 boys.

• Obtain an alphabetized list of all the students in the school and select every seventh student.

• Place all the names of the students in Mrs. Walsh's math class in a hat and randomly select 10 students.

Vanessa’s class is studying the number of car commercials on television between 6 p.m. and 8 p.m. for five days. Which is the best sample for Vanessa to use?

• The commercials between 6 p.m. and 8 p.m. on each day

• The first five commercials each of the five days

• The commercials shown between 6 p.m. and 7 p.m. on a randomly chosen day

• The commercials shown between 6:30 p.m. and 7:30 p.m. on three randomly chosen days

To predict the performance of her first period class on their next quiz, a teacher randomly selects eight students from the class and takes the mean of their scores on the last quiz. Is this sample representative of the​ class's performance on the quiz?

• ​No, because the students were chosen from the best students in the class.

• ​Yes, because the students were chosen based on their class average.

• ​No, because it is a simple random sample.

• ​Yes, because it is a simple random sample.

The sample represents the population.

Choose the answer that says "Representative Sample"

• Random Sample

• Biased Sample

• Representative Sample

A school principal wants to see which subject the 695 students in his school liked best. Which choice BEST represents a representative sample?

• The girls in the school.

• 1 classroom for each grade

• All the students in the school.

• The students making a B in math.

A survey was distributed to determine food preferences for Middle School students. Which sample is most the representative for this survey?

• A group of High School students during a PE class.

• A group of parents of local Middle School students.

• 10 Elementary School students from each of the 5 local Elementary Schools.

• 20 randomly selected students from 6th, 7th, and 8th grade from each local Middle School.

The sample represents the population.

Choose the answer that says "Representative Sample"

• Random Sample

• Biased Sample

• Representative Sample

To try to predict the outcome of the vote for the school board election school board election​, a town manager used random numbers to pick 100 registered voters. She then called these voters and asked how they planned to vote. Is the sample taken in this problem representative of the population?

• No, because it does not contain the same number of subjects as the population.

• ​Yes, because it is a systematic sample.

• ​Yes, because it is a simple random sample.

• ​Yes, because it contains the same number of subjects as the population.

You want to study a random sample of 4 out of 26 students in your class. Describe a process you could use to create a random sample with 4 subjects.

• Assign each student a number in alphabetical​ order, then select 4 random numbers.

• Select 4 students who sit close to you.

• Select the 4 students whose names come first alphabetically.

• Assign each student a​ number, then select students 1 through 4.