Only members of the population who are easily accessible are selected
What is undercoverage bias?
Call-in radio shows that solicit audience participation in surveys on controversial topics (abortion, affirmative action, gun control, etc.) are examples of __________ bias.
What is voluntary bias?
Pick the best method of data collection (observational study, experiment or survey): A study of the effects of eating oatmeal on lowering blood pressure. Group A would eat oatmeal and group B would not eat the oatmeal. Each groups blood pressure measurements would be compared.
What is an experiment?
The employees of a company are split into two groups, men and woman. In each of the groups 100 individuals are chosen at random to ask about their recent raise. This is an example of _______ sampling.
What is stratified sampling? Remember with cluster sampling you take all the members from the chosen groups. In a stratified sample you group then sample again in each group.
True or False...if you have bias in your sample, you can get rid of it by increasing your sample size?
FALSE!!! Throw out your data and start again using a random sample!!
A college counselor would like to select a simple random sample of all 525 students in the college. She uses the numbers from 001 to 525 to number the students in a college database and then uses a random number table to choose her sample of 30. What numbers correspond to the first 3 students chosen? 06385 61327 51790 63618 23145 46124 20031
What is 063, 132, 182?
A survey question was asked - "Why is drinking milk good for you?" Pick whether this question would lead to an overestimate or underestimate of the results about milk.
What is overestimate?
A car company is interested in the reliability of one of their cars. They select a dealership and ask the people who bring their cars in for service about the reliability of the cars. What type of sampling is this?
Convenience Sampling---horrible! Not everyone goes to the dealer for service. People who don't have service issues aren't going to be represented, etc.
Bias often occurs when the survey sample does not accurately represent the population. The bias that results from an unrepresentative sample is called _______.
What is selection bias? Undercoverage, non-response or voluntary bias can occur