# Been to the movies An opinion poll calls 2000 randomly

Chapter , Problem R4.5

(choose chapter or problem)

QUESTION:

Been to the movies? An opinion poll calls 2000 randomly chosen residential telephone numbers, then asks to speak with an adult member of the household. The interviewer asks, How many movies have you watched in a movie theater in the past 12 months? In all, 1131 people respond. (a) Identify a potential source of bias related to the question being asked. Suggest a change that would help fix this problem. (b) Identify a potential source of bias in this survey that is not related to question wording. Suggest a change that would help fix this problem. s Distinguish between an observational study and an experiment. s Explain how a lurking variable in an observational study can lead to confounding.

QUESTION:

Been to the movies? An opinion poll calls 2000 randomly chosen residential telephone numbers, then asks to speak with an adult member of the household. The interviewer asks, How many movies have you watched in a movie theater in the past 12 months? In all, 1131 people respond. (a) Identify a potential source of bias related to the question being asked. Suggest a change that would help fix this problem. (b) Identify a potential source of bias in this survey that is not related to question wording. Suggest a change that would help fix this problem. s Distinguish between an observational study and an experiment. s Explain how a lurking variable in an observational study can lead to confounding.

(a) Potential source of bias: The question does not differentiate between people who go to the movies because they love seeing movies in movie theaters and those who go to the movies under certain circumstances (e.g. special events). Suggested change: Ask "How many movies have you seen in a movie theater in the past 12 months for enjoyment?"

(b) Potential source of bias: This survey does not differentiate between those who are reached on their home phone and those who are reached on their mobile phone. Suggested change: Pre-screen