Sampling Showdown Worksheet
AP Statistics & Research Methodology
SAMPLING SHOWDOWN
Identifying Sampling Techniques & Detecting Bias
NAME: ________________
DATE: ________
CLASS: _______________
SCORE: _______ / 20
The Scenario: Civic Transit Initiative
A mid-sized city is evaluating community support for a proposed $45M public transit expansion (including new light rail lines and protected bike paths). For each sampling method below, (a) identify the sampling technique, and (b) analyze potential sources of bias (if any) with a clear justification.
1
You stand outside the main entrance of the public library at 2:00 PM on a Tuesday and survey every 10th person who walks out.
Technique:
Justification & Potential Bias:
2
You divide the city into 4 distinct geographic zones (North, South, East, West) and randomly select exactly 50 registered residents from each zone to survey.
Technique:
Justification & Potential Bias:
3
You ask 30 of your close friends, neighbors, and family members at a weekend neighborhood backyard barbecue for their opinions.
Technique:
Justification & Potential Bias:
4
You obtain an official municipal database of all registered residents, assign each resident a unique ID, and use a computer's random number generator to select 200 residents.
Technique:
Justification & Potential Bias:
5
You post a flyer with a QR code linking to an online survey on local community Facebook groups and Nextdoor pages, inviting people to share their opinions.
Technique:
Justification & Potential Bias:
Unit 1: Data Collection & Sampling Methods Page 1 of 2 Transit Survey Investigation
SAMPLING SHOWDOWN — Part II
Student Name: ____________________________
6
You randomly select 5 apartment complexes in the city out of 60 total, and survey every single resident living in those 5 chosen complexes.
Technique:
Justification & Potential Bias:
7
You categorize the city population by daily commute type (solo drivers, carpoolers, train/bus riders, and cyclists) and randomly survey 40 people from each group.
Technique:
Justification & Potential Bias:
8
You obtain an alphabetical list of all registered voters in the city database and select every 25th name on the list to receive a phone call.
Technique:
Justification & Potential Bias:
9
You stand at the bus stop closest to your home at 8:00 AM on a Monday and interview the first 20 people you see waiting for the bus.
Technique:
Justification & Potential Bias:
10
The city is divided into 30 distinct voting precincts. You randomly select exactly 3 of these precincts and survey every single voter living within them.
Technique:
Justification & Potential Bias:
Submission Criteria: ✔️ 10/10 Techniques Identified ✔️ Correct terminology (SRS, Stratified, Cluster, etc.) ✔️ Specific bias identified where applicable
Unit 1: Data Collection & Sampling Methods Page 2 of 2 Transit Survey Investigation
Sampling Showdown Teacher Guide
AP Statistics & Research Methodology
SAMPLING SHOWDOWN
Teacher Solutions & Grading Guide
COMPREHENSIVE KEY Total Points: 20
Grading Rubric (2 Points Per Scenario)
1.0 Point: Correct sampling technique identified (accept abbreviations).
1.0 Point: Reasonable justification and realistic source of bias explained.
1
Stand outside the public library at 2:00 PM on a Tuesday and survey every 10th person walking out.
Correct Technique: Systematic Sampling
Justification & Bias Analysis:
Justification: Uses a fixed interval rule (every 10th person).
Bias: Undercoverage / Convenience. Tuesday afternoon library users skew toward retirees and students, who may value public transit differently than working-class commuters.
2
Divide city into 4 zones (North, South, East, West) and randomly select 50 residents from each.
Correct Technique: Stratified Sampling
Justification & Bias Analysis:
Justification: Population divided into zones (strata) and SRS taken from each zone.
Bias: Unbiased. Ensures geographic representation. Residents in less-populated zones have a higher selection probability (can be weighted during analysis).
3
Ask 30 of your close friends, neighbors, and family members at a weekend backyard barbecue.
Correct Technique: Convenience Sampling
Justification & Bias Analysis:
Justification: Sample chosen entirely based on ease of access and proximity.
Bias: Selection Bias. Friends and family likely share socioeconomic profiles and political opinions with the researcher, leading to a highly unrepresentative sample.
4
Obtain database of registered residents, assign IDs, and use a random number generator to select 200.
Correct Technique: Simple Random (SRS)
Justification & Bias Analysis:
Justification: Every resident and every group of 200 has an equal probability of selection.
Bias: No selection bias, but potential for Non-Response Bias (selected residents refuse to answer) or Undercoverage of unlisted households.
5
Post online survey QR code to neighborhood Facebook/Nextdoor groups inviting people to respond.
Correct Technique: Voluntary Response
Justification & Bias Analysis:
Justification: Subjects self-select to participate in response to an open appeal.
Voluntary Response Bias. Over-represents passionate individuals (e.g., active transit advocates or angry taxpayers) while missing moderate voices.
