Sampling and Bias

I want to estimate the proportion of adults in San Diego County who believe that the voting age should be reduced to 17. I get a list of all registered voters in the county and separate that list into several geographic regions and then collect an SRS from each geographic region. What kind of sampling method is this?

• Simple Random Sample

• Cluster Sample

• Stratified Sample

• Systematic Sample

I want a representative sample of likely voters. I use a telephone directory to randomly select 200 people. What is the most apparent bias?

• Undercoverage

• Nonresponse

• Response

• Voluntary Response

A principal orders t-shirts and wants to check some of them to make sure they were printed properly. She randomly selects 2 of the 10 boxes of shirts and checks every shirt in those 2 boxes.

• Simple Random Sampling

• Stratified Random Sampling

• Cluster Random Sampling

• Systematic Random Sampling

A teacher wants to know the average time spent doing homework by the students in her class of 20 girls and 5 boys. She selects the five closest to her desk. What type of sampling method is being used?

• simple random

• Voluntary Response

• Convenience

• Systematic Random

Which method is described?

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

• simple random

• voluntary response

• systematic

• convenience

Which method is described?

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

• systematic

• simple random sample

• convenience

• voluntary response

16 out of the 20 people who called into a radio station said that they enjoy the station's morning programming. What type of bias is demonstrated here?

• Voluntary Response Bias

• Nonresponse Bias

• Undercoverage Bias

• Selection

I want to estimate the proportion of people in North Palm Beach who own cats. I stand outside a NPB pet store and ask every 4th person whether they own a cat or not. What is the most prominent kind of bias evident?

• Undercoverage

• Response

• Non-Response

• Voluntary Response

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

Which method is described?

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

• systematic

• simple random sample

• voluntary response