Bias in Surveys

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

Comment on whether or not this survey exhibits bias, and explain your reasoning:TITLE: Survey on Local Voting Preferences. OBJECTIVE: To understand the voting preferences of residents in the town. METHODOLOGY: A questionnaire was mailed to 1,000 registered voters. Out of these, only 200 completed and returned the survey. QUESTIONS: (a) Preferred candidates in the upcoming election, (b) Key issues influencing their vote, (c) and Demographic information such as age and income

Tags

CCSS.RL.11-12.6

Comment on whether or not this survey exhibits bias, and explain your reasoning:

TITLE: Survey on Household Energy Usage. OBJECTIVE: To assess the energy consumption patterns of households in Pacifica. METHODOLOGY: A random sample of 500 Pacifica households was selected using the city’s utility records. Surveys were distributed via postal mail to ensure all households had an equal chance of participation. Follow-up reminders were sent to maximize response rates. QUESTIONS: (a) Monthly energy usage, (b) types of energy sources used, (c) energy-saving practices, (d) and demographic information such as household size and income.

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CCSS.RI.11-12.7

CCSS.RI.9-10.7

CCSS.RL.11-12.7

CCSS.RL.8.7

CCSS.RL.9-10.7

Decide if the following statement is true or false and explain your reasoning:

Using the right sampling techniques effectively eliminates bias.

Answer explanation

This is incorrect. It is impossible to completely eliminate bias in any study. Researchers focus on minimizing bias as much as possible through careful design and methodology, but some degree of bias is always inevitable due to limitations in data collection or inherent factors in the study context...(oh, and there's the part about humans being fallible creatures that will always have flaws).

Why do we want our samples to be random?

• To decrease the margin of error

• To increase our confidence

• To decrease variability

• To decrease bias

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

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