Populations and Sampling Assessment Practice

Unbiased sampling is:

• when you choose the group you think will give you the answer you want, accept volunteers or survey by convenience

• when any member of the population is equally likely to be chosen for the sample

Complete the definition:

A _________ consists of all subjects (human or otherwise) that are being studied

• Statistics

• Number

• People

• Population

• Pueblo

Population or Sample?

A survey of 1353 American households found that 18% of the households own a computer.

• Population

• Sample

Population or Sample?

A recent survey of 2625 elementary school children found that 28% of the children could be classified obese.

• Population

• Sample

The average weight of every person entering the mall within 3 hour period was 146 lb.

• Population

• Sample

Population or Sample?

A factory overseer selects 40 threaded rods at random from those produced that week at the factory, then she tests their tensile strength.

• Population

• Sample

Population or Sample? A quality control engineer is curious about the thickness of paint on a car at her factory. She randomly selects 30 points on the car and measures the paint thickness at each of those points.

• Population

• Sample

Population or Sample?

All of the teachers in a school are surveyed on their meeting time preferences.

• Population

• Sample

Population or Sample?

A police officer measures the speed of all the cars that pass a specific point on the road during his shift.

• Population

• Sample

A musician wanted to see what people who bought his last album thought about the songs.
Which choice best represents a sample?

• Every person who bought the album.

• A selection of people who didn't want to buy the album.

• 250 girls who bought the album.

• A selection of 3,294 people who bought the album.