Vocabulary

Unbiased Sample: A sample that is selected so that it is representative of the entire population.

Biased Sample: A sample in which one or more parts of the population are favored over others.

Simple Random Sample: A sample that is chosen without any preference, representative of the entire population.

Systematic Random Sample: A sample in which the items in the sample are selected according to a specified time or item interval.

Convenience Sample: A sample that includes members of the population that are easily accessed.

Voluntary Response Sample: A sample that involves only those who want to participate.

Concepts

Determine whether statistical conclusions are valid or invalid and use the given information to make predictions for large populations based on smaller sample spaces.

Rules

Read the given scenario. Compare the situation to the given definitions. 

Example

All residents of a town received a postcard asking them to take a survey online. 
Select what type of sample this represents.

Solution

Since the residents have to decide whether to complete the survey, it is a voluntary response sample.

Pre-requisite Skills

None.