Sampling Bias and Response Bias

I want to estimate the proportion of all adults in Chula Vista who graduated from high school. I select a random sample of addresses and go to those houses. When an adult answers the door, I ask if they had graduated from high school. If a child answers the door, I ask for an adult. If there is none there at the time, I return at another time to complete the survey. What is the most prominent bias?

• Non-response bias

• Response bias

• Voluntary response bias

• Undercoverage

A store manager wants to estimate the proportion of all the customers of the store who would use store credit card for their purchases. The manager selects a random sample of 1,000 customers from their customer loyalty program list and sends them a survey asking if they would be interested in applying for a store credit card. Of the 78 customers who responded to the survey, 70 of them expressed interest in applying for a store credit card. Should the manager be concerned about these results? If so, why? Select all that apply.

• The manager should not be concerned about these results.

• Yes, because he should have asked more customers.

• Yes. Due to the low response rate, those who responded might be the people who are most interested in a store credit card and overestimate the population proportion of all customers who would be interested in a store credit card.

• Yes. Since he only asked customers from the store loyalty program, those customers may be more interested in a store credit card than all customers.

A store manager wants to estimate the proportion of all the customers of the store who would use store credit card for their purchases. The manager selects a random sample of 1,000 customers from their customer loyalty program list and sends them a survey asking if they would be interested in applying for a store credit card. Seventy-eight customers respond to the survey. What kinds of biases are evident in this scenario? Select all that apply.

• Non-Response Bias

• Response Bias

• Undercoverage Bias

• Volundary Response Bias

An employer wants to know how their 500 employees like working for them. Which is the most representative sample?

• Ask the first 75 people to show up for work

• Randomly select the names of 10 employees

• Poll the Employees of the Month for the past year

• Randomly select the names of 75 employees

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.

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.

The School Dance Committee conducts a survey to find what type of music students would like to hear at the next dance. Which sampling method is least likely to result in a biased sample?

• Call the top 20% of the senior class. 

• Interview every 10^th student as they enter the school.

• Ask every 5^th person leaving a school jazz band concert.

• Set up a hip-hop only website where students can list their 3 favorite songs if they open up the link.

At a middle school, the 7th graders will conduct a survey for where to go on a field trip. Which method will result in the least biased decision?

• to randomly ask 8th grade students who went on a field trip last year

• to randomly choose some 7th grade students to select a location

• to ask all 7th grade teachers and administrators for a location

• to ask the student council to choose a location