AP Statistics Sampling Types and Bias

A group of librarians is interested in the numbers of books and other media that patrons check out from their library. They examine the checkout records of 150 randomly selected adult patrons.

• The population is all adult patrons of the library; the sample is the 150.

• The populations is all patrons of the library; the sample is the adult patrons of the library.

• The population is all patrons is all patrons who check out at least 1 book from the library; the sample is the 150 patrons selected.

If you have 1,000 schools on the list, number them from 000 to 999 and read the table three digits at a time. What are the first five schools in this sample?

• 24, 19, 83, 72, 41

• 241, 983, 724, 152, 579

• 2419, 8372, 4152, 5761, 0849

Identify the Sample: A restaurant wants to know if customers buy dessert when they eat out. As people leave the restaurant one evening, 20 people are surveyed at random. Eight people say they usually order dessert when they eat out. The restaurant concluded that most customers do not order dessert.

• 20 customers

• 8 customers

• All customers

• Dessert

Identify the type of sampling used:

Interview every 10th student who enters the school in the morning.

• simple random sample

• voluntary response sample

• systematic sample

• convenience sample

Identify the type of sampling used:

Assign each car in a dealership a number and then use a random-number table to select the cars to be inspected.

• systematic sample

• simple random sample

• convenience sample

• voluntary response sample

Identify the type of sampling used:

Marianne wanted to know students' opinion on the new schedule at school. She survey's the first 30 students who come into her class.

• Convenience Sampling

• Systematic Random Sampling

• Simple Random Sampling

• Volunteer response

Disneyland often surveys its guests as they exit a restaurant during their visit. The surveyor stands at the restaurant exit, counts the number of people leaving, and surveys every 25th guest.
This is a form of:

• Simple Random Sample

• Stratified Random Sample

• Voluntary Response

• Systematic Random Sampling

An independent research company wants to go door to door to survey people in the city of West Palm Beach. The company decides to number all blocks within the city limits, randomly choose 1 block, and then survey all households on that block.

This is an example of:

• Simple Random Sample

• Stratified Random Sample

• Cluster Random Sample

• Systematic Random Sampling

Identify the type of sampling used:

A teacher splits her classes up by period. She then uses a RNG to select 10 students from each period to participate in a survey.

• Stratified Random Sample

• Systematic Random Sample

• Cluster Random Sample

• Biased Sample

Why do we randomly select our samples?

• for control

• reduce bias

• so we don't get the same answers from everyone

• to eliminate confounding results