Biased or Unbiased Samples

To determine the quality of service customers receive, an airline sends an e-mail survey to each customer after the completion of a flight. Will this sample be biased or unbiased?

• Unbiased because each customer receives an email.

• Unbiased because the survey will get many responses.

• Biased because the survey will not get enough responses.

• Biased because not every person reads their email.

Choose the best sample.

• Sample A

• Sample B

Which of the following is NOT needed in order to be considered an unbiased sample?

• Selected at random

• Representative of the entire population (everyone has a chance of being chosen)

• Representative of at least half of the population

• Large enough to provide accurate data

The manager of the zoo would like to survey its visitors to determine their favorite exhibit. Which sample below would be unbiased?

• 20 random people in the food court

• Every 10th person who enters the zoo

• 50 random people at the tiger exhibit

• 3 people who are buying souvenirs

A high school is conducting a survey to see how many students have part-time jobs. Which sample below would be unbiased?

• every 10th

  student that

  enters a school football

  game

• 100 random students in the

  school parking lot

• five random students in

  each homeroom

• 50 students from the band and chorus

To determine how much money college students spend on clothes each semester,a researcher surveys 450 college students as they leave the university library. Is this sample biased or unbiased?

• Biased because not everyone goes to the library

• Unbiased because 450 people is enough people to provide accurate data

• Biased because 450 is not enough people to provide accurate data

• Unbiased because everyone goes to the library

A school surveys all 7th grade boys to determine what to sell in the school store.  This sample is _________.

• Biased

• Unbiased

• Representative

• Peanut butter cups

A school survey asked 50 girls to identify their favorite items on the school cafeteria menu. This sample is ________________.

• Biased

• Unbiased

• Representative

• Numerical

A student wants to know which type of pizza the students at his high school prefer. Which option would give a unbiased, representative sample:

• Asking all the students in the hot lunch line.

• Asking 10 random students from each homeroom.

• Asking every other student who gets off a school bus.

• Asking all the 10th graders.

Choose the true statement(s) about the census and sample shown.

• The sample could be considered too small.

• The sample is biased because is does not include everyone.

• The sample is representative of the population's sub-groups.