Determine If a Sample Is Representative of a Population

The city council in Middlefield wants to know if residents are in favor of a traffic camera at the main intersection in town. Which example is likely to produce a representative sample?

• Drivers who reside in Middlefield

• Residents randomly chosen from the town register

• All residents of Middlefield

• All people with a five-letter last name

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.

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.

When a sample does not accurately represent the population it is a:

• Unbiased sample

• Biased sample

You want to estimate the number of students in a high school who ride the school bus. Which sample is best?

• 4 students in the hallway

• All students in the marching band

• 50 seniors at random

• 100 students at random during lunch

Are all quarters in circulation the sample or the population?

• Sample

• Population

Which one is the sample?

• All books in library

• 10 library books

Choose the best sample.

• Sample A

• Sample B