Worked examplesThree real random sampling and data collection questions
From the practice pool, not the mock papers — each with the reasoning that produces the answer.
100% of them come with a figure. Reading the graph or diagram correctly is most of the work here before any content knowledge applies.
100% test a single AP skill: Selecting Statistical Methods. That makes this topic unusually predictable to prepare for.
Selecting Statistical Methods · with figure
The after-school robotics league alpha cycle has lists of teams within each mentor. A planner wants each mentor represented when estimating battery swap completion. Which design is most appropriate?
- AChoose one mentor and survey everyone in it.
- BA large convenience sample removes selection bias because increasing sample size alone makes the sample representative.
- CInvite the first 90 teams who notice the prototype cart.
- DLet staff pick teams they think are typical.
- EStratify by mentor, then randomly select teams within each stratum.correct
Why E is correct
Stratified random sampling is best because the planner first separates teams by mentor and randomly samples within every group, ensuring representation while preserving randomness.
Stratified random sampling for after-school robotics league alpha cycle: the important cue is the after-school robotics league alpha cycle setting. Match the method to the way the data are collected or the statistic is computed, then state the conclusion in the language of the stem.
Selecting Statistical Methods · with figure
The youth orchestra camp alpha cycle has lists of musicians within each instrument section. A planner wants each instrument section represented when estimating practice log accuracy. Which design is most appropriate?
- AA large convenience sample removes selection bias because increasing sample size alone makes the sample representative.
- BStratify by instrument section, then randomly select musicians within each stratum.correct
- CChoose one instrument section and survey everyone in it.
- DInvite the first 97 musicians who notice the metronome app.
- ELet staff pick musicians they think are typical.
Why B is correct
Stratified random sampling is best because the planner first separates musicians by instrument section and randomly samples within every group, ensuring representation while preserving randomness.
Stratified random sampling for youth orchestra camp alpha cycle: the important cue is the youth orchestra camp alpha cycle setting. Match the method to the way the data are collected or the statistic is computed, then state the conclusion in the language of the stem.
Selecting Statistical Methods · with figure
The fitness trail study alpha cycle has lists of walkers within each time block. A planner wants each time block represented when estimating mile-marker usage. Which design is most appropriate?
- AInvite the first 104 walkers who notice the trail counter.
- BA large convenience sample removes selection bias because increasing sample size alone makes the sample representative.
- CChoose one time block and survey everyone in it.
- DStratify by time block, then randomly select walkers within each stratum.correct
- ELet staff pick walkers they think are typical.
Why D is correct
Stratified random sampling is best because the planner first separates walkers by time block and randomly samples within every group, ensuring representation while preserving randomness.
Stratified random sampling for fitness trail study alpha cycle: the important cue is the fitness trail study alpha cycle setting. Match the method to the way the data are collected or the statistic is computed, then state the conclusion in the language of the stem.
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Last reviewed 2026-08-28. Topic and unit names follow the
College Board course framework. Question counts describe the PrepScore practice bank, not the exam.