A question about causation asks whether a program produced an outcome, not just whether two groups have different averages. Separate random selection, which chooses who is studied, from random assignment, which chooses who gets the program. If school schedules determine which schools offer a workshop, the schedules or related school differences could also explain the outcome.
Hints
- Hint 1
Random sampling means picking participants by chance to be measured. It can help a result represent a larger group, but it doesn't decide who gets the workshop. Who made that decision here?
- Hint 2
A confounding variable is another difference between groups that could help explain their results. If school schedules determine which schools offer the workshop, what could explain a difference in on-time submissions besides the workshop?
Step-by-step
Check who formed the workshop groups
Step 1Separate selection from assignment
No Desmos needed. This asks how the groups were formed, not for a calculation. The district randomly picked schools and students to track. That's random sampling, or choosing whom to study by chance. It didn't decide which schools offered the workshop.
- Step 2
Find what prevents a causal conclusion
The principals chose whether to offer the workshop based on their schools' schedules. Schools with room in their schedules might differ in other ways that affect on-time submissions. So the 9-percentage-point difference doesn't show that the workshop caused the difference.
- Step 3
Assign the workshop by chance
Because whole schools offer the workshop, randomly assign five of the 12 selected schools to offer it and the other seven not to. That's random assignment: chance, rather than scheduling, forms the groups. Random sampling picks who is studied; random assignment picks who receives the workshop. The district could then support a causal conclusion about offering it for tenth-grade students at the selected schools. Choice D.