Sampling Methods

A _______ sample selects individuals that are easy to get to. The sample is usually not representative of the population.

• Voluntary Sample

• Simple Random Sample

• Convenience Sample

• Stratified Sample

A _______________________ sample allows the individuals to self-select. Often, the individuals who participate differ from those who do not, making the sample not representative of the population.

• Simple Random Sample

• Voluntary Response

• Multistage Sampling

• Convenience Sample

A _______________________ sample uses random selection to choose individuals for the sample.

• Voluntary Response

• Simple Random Sample

• Convenience Sample

• Multistage Sampling

A ____________________________ sample first breaks the individuals into categories called strata. Within each of these categories, any given individual has an equal chance of being selected.

• Convenience Sample

• Multistage Sampling

• Stratified Random Sample

• Simple Random Sample

When a sample does not give all members of the population an equal chance of being represented, the sample suffers from _________________.

• Undercoverage

• Non-Response

• Voluntary Response

• sample representation

When a sample is missing results from individuals who choose not to participate, the sample suffers from _________________.

• Undercoverage

• Non-response

• voluntary response

• multi stage sampling

Do all people have an equal, random chance of being selected? Answer yes or no.

You walk through a large crowd and interview the first person who makes eye contact with you.

• Yes

• No

Do all people have an equal, random chance of being selected? Answer yes or no.

You number people 1-24 and then roll 4 dice and add them together to see which person to choose.

• Yes

• No

You want to study the favorite juices of Olmsted County residents. To do this, you go through the phone book and randomly select 70 people to call. Of those you call, 32 answer and answer your questions.

What is the population?

What is the sample? What is the sample size?

Is there any undercoverage? If yes, who?

Is there any non-response? If yes, what is the non-response rate?

What is a potential source of bias in the question below?

Many fast food restaurants want feedback from their customers, so they offer a free cookie/Whopper/etc. on the back of their receipts if you call in and take a short phone survey. After one student shared this fact with many friends, the number of surveys taken at local restaurants greatly increased.