Bias Sample

Determine if the following study is biased.

A senator wants to how she is doing. She sends a survey to 1000 registered voters in her party.

• Biased

• Unbiased

When a sample does not accurately represent the population it is a:

• Unbiased sample

• Biased sample

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 of the following doesn’t result in some form of bias?

• Choosing AP students to survey regarding their GPA in order to estimate the average GPA in a school.

• Polling a group of potential voters outside a Republican campaign office in order to estimate the proportion of city residents who favor a particular candidate.

• Surveying people who work in the marketing department of a large corporation in order to assess employee satisfaction with management policies.

• Choosing a stratified random sample of juniors and seniors at a high school in order to estimate the proportion of juniors and seniors who plan to go on to college.

• Asking shoppers leaving a grocery store if they think groceries should cost less in order to estimate the proportion of city residents who think groceries cost too much.

Tanya wants to know the percent of people likely to attend the upcoming musical at school. She asks each person in the musical how many people they know who are coming to make a prediction. Why is this sample biased?

• Drama students are more likely to lie.

• Musicals are better attended than plays.

• The drama teacher was not asked.

• The sample is not random and not representative of the entire school population.

Answer explanation

The sample is not random and not representative of the entire school population, as it only includes people involved in the musical, leading to bias.

In order to estimate the proportion of students that text while driving, a school administrator selects a simple random sample of students from a list of all students at the school who have parking permits. The students are called to the office, one at a time. The administrator asks each student, “Do you text while driving, even though you are not supposed to?” Based on the survey, the administrator estimates that only 2% of students with parking passes text while driving. What potential bias is present in the design of this survey and what is the likely direction of the bias?

• The sample proportion is likely an underestimate of the population proportion due to response bias.

• The sample proportion is likely an underestimate of the population proportion due to undercoverage.

• The sample proportion is likely an underestimate of the population proportion due to nonresponse.

• The sample proportion is likely an overestimate of the population proportion due to response bias.

• The sample proportion is likely an overestimate of the population proportion due to undercoverage.

4.  Carlos wants to know the favorite sport of people at his school so he asks his baseball team.

• Biased

• Unbiased

Leslie surveyed the 9 youngest students in the elementary school.  Is this sample of the students in the school likely to be representative of all the students in the school?

• yes

• no

Select the question with the least amount of bias.

• Don't you think that Milky Ways are awesome?

• On a scale of 1-10, how terrible are Milk Duds?

• Select a candy that you like below: gummy worms, laffy taffy, jelly beans

• Select a candy that you like below: gummy worms, laffy taffy, jelly beans, none of the above