Exploring Random Sampling

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 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.

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

A movie theater considers upgrading to offer luxury seating. The manager randomly surveys​ 1,200 residents who live within 10 miles of the theater. What is the sample in this​ situation?

• The​ 1,200 residents surveyed

• ​1,500 randomly surveyed customers of the movie theater

• All of the movie​ theater's customers

• All residents who live within 10 miles of the theater

Suzie examined 7 flowers in each planter at the mall.  Each planter has an equal number of flowers.  Is this sample of the flowers at the mall likely to be representative?

• yes

• no

A teacher examined 17 different tests from each of her math classes.  Each class had the same number of tests.  Is this sample of the tests likely to be biased?

• yes

• no

Without looking, Christine took 2 flash cards out of her box of flash cards.  Is this a random sample of the flash cards?

• yes

• no

Emma selected 5 essays from each student in her class.  Each student wrote the same number of essays.  Is this sample of the essays written by the class likely to be representative?

• yes

• no