SLIDES - Identifying Bias

Open Ended

Do Now

How can bias affect the results of a statistical study? Have you ever noticed bias in a poll, survey, or study you have done?

Multiple Choice

Which scenario best illustrates the concept of undercoverage bias?

• A phone survey that only calls landline numbers, missing those who only use mobile phones.

• A study where participants are asked to recall what they ate last year.

• An online feedback form filled out voluntarily by customers.

• A clinical trial where the medication is administered only to a subset of the group.

Open Ended

Which of the two wordings do you think will produce a higher percent of those saying "Yes"? Explain your answer.

Multiple Choice

Is this question biased or fair?

"Do you prefer the natural beauty of hardwood floors over outdated laminate?"

• biased

• fair

Open Ended

A soft drink company calls 500 people at random and asks, "Is our product or our rival's product the best soft drink on the market?" Is this question biased? How?

Multiple Choice

City Council wants to assess the public’s opinion on construction of a new state prison. They place an announcement in the newspaper asking people to call their council representatives to register their opinions.

• Self-Selection

• Undercoverage

• Non-Response

Multiple Choice

Which question is unbiased?

• Does the school have the right to enforce a dress code?

• Do you think the mayor is doing a good job in spite of his questionable character?

• Do you prefer daytime or evening television programming?

• Do you think the government should be allowed to cut down trees willy-nilly to build a new highway?

Multiple Choice

What type of bias appears present in this situation?

To understand how Virginians feel about the upcoming election, you survey 89 Shenandoah County residents.

• voluntary response bias

• response bias

• non-response bias

• undercoverage

Multiple Choice

Alex is conducting a survey for a car company. She decides to start by interviewing some people in her neighborhood. She prepares a questionnaire and emails it to 50 neighbors who own cars. Of those neighbors, 24 respond. Why is this sample likely to be biased?

• Alex sent a questionnaire by email instead of going door to door.

• Alex sent the questionnaire only to those who live near her.

• Not everyone who got the questionnaire responded.

• Those who got the questionnaire may not have responded on time.

Open Ended

How would you re-write this question to be less biased? Think-Pair-Share

"Do you believe that increasing property taxes on Middle-Class reisdents is bad for the economy?"

Multiple Choice

Cheap and Fast gas station is conducting a consumer satisfaction survey. Which method of collecting data would most likely lead to a biased sample?

• interviewing every 5th customer to come into the station

• interviewing customers chosen at random by a computer at the checkout

• interviewing customers who call an 800 number posted on the customers' receipts

• interviewing every customer who comes into the station on a day of the week chosen at random out of a hat

Multiple Choice

What is convenience sampling?

• Sampling individuals who are easily accessible

• Sampling individuals randomly from a population

• Sampling individuals based on specific criteria

• Sampling individuals from a diverse group

Poll

How confident do you feel about this topic now?

• Very confident
• Somewhat confident
• Not confident