Sampling Methods Review

A sample is:

• a subset of the population.

• the entire population.

• a group similar to the population.

• something free you get at Costco.

Mrs. Doebler wants to know how many of her students take notes while they watch homework videos. She has 160 students total. She randomly selects 15 of them and sends them a survey asking if they take notes. The survey is just a yes/no question.

• The 15 randomly selected students

• Sample

• The % in the sample who take notes

• Parameter

• All 160 students

• Statistic

• The true % of students who take notes

• Population

Sammy wants to know what percent of students at her high school have a driver’s license. She surveys all students in her statistics class and finds that 68% of the students in her sample have a driver’s license. What type of sample did Sammy obtain?

• Simple random sample

• Stratified random sample

• Convenience sample

• Voluntary response sample

each item or person in the population is as likely to be chosen as any other

• biased sample

• systematic random sample

• unbiased sample

• simple random sample

What type of sampling is shown?

• Simple Random Sample

• Systematic Sample

• Cluster Sample

• Stratified Sample

I want to estimate the proportion of all adults in Rancho who graduated from high school. I select a random sample of addresses and go to those houses at noon. I ask whoever answers the door if they graduated from high school.

Why is this survey biased?

• Nonresponse: some people might refuse to participate in the survey

• Wording of the question: the question might confused people who are being surveyed

• Voluntary response: People do not have to participate in the survey

• Undercoverage: I'm missing the people who are at work at noon

I want to estimate the percent of people in Rancho who own cats. I stand outside a local pet store and ask every 4th person whether they own a cat or not. Why is this biased?

• Undercoverage: I'm missing the people who don't shop at a pet store

• Observational study: this is not a valid survey

• Non-Response: Some people may refuse to do the survey

• Voluntary Response: doing the survey is optional and I'll only get extreme opinions

A beverage company wanted to see if people in the United States liked their new logo. Which choice best represents a population?

• A selection of logo artists.

• Every person in the United States.

• A selection of shoppers from different states.

• 3,800 children age 5 - 15

• A

• B

• C

• D

• E

• A

• B

• C

• D

• E