Unit quiz: Explanation, causation and research design

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5 questions · 80% to pass · no timer. This quiz checks the lessons in this unit. These authored questions assess recognition and application of the taught distinctions, not professional qualification. You may review the lessons and retry. Repeat attempts reuse the question bank; a remembered answer is not proof of transfer to a new situation.

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Question 1

A falling barometer can predict a storm, but smashing the barometer does not prevent it. Atmospheric conditions account for both the reading and weather change. The reading is an indicator rather than the storm-producing mechanism. A good predictor can therefore be a poor intervention target.

Why is breaking the barometer not an explanatory intervention on the storm?The reading is an effect or indicator of conditions, not their causeAny successful predictor must directly produce its outcome

Question 2

Hot weather increases both ice-cream sales and swimming, while greater swimming exposure can increase drowning incidents. Ice-cream sales and incidents may therefore rise together without ice cream causing drowning. The common weather-related pathway supplies an alternative to the direct-cause story.

What should be investigated before claiming ice-cream sales cause drowning?Whether the two quantities can be mentioned in one sentenceThe shared weather and exposure pathway

Question 3

Volunteers are randomly assigned to two teaching methods. The assignment improves the comparison among volunteers. It does not make volunteers a random sample of all learners. If one method drives more struggling learners to drop out, comparing only final completers can introduce selection problems despite the initial randomization.

What does random assignment alone not establish?That the volunteers represent all learnersThat allocation was independent of participant characteristics in expectation

Question 4

Imagine a program admits applicants for exceptional research or exceptional performance. Among admitted students, someone with weaker research must often have stronger performance to qualify. A negative association can emerge within admissions even if the traits are independent in the applicant population. Admission is the common effect selected on.

Why can restricting attention to admitted students create a misleading association?Admission necessarily causes the applicants’ original traitsAdmission is influenced by both traits and selection conditions on it

Question 5

A researcher plans to test one outcome, finds little support, then discovers a striking subgroup pattern while exploring many divisions. The subgroup result may be worth investigating, but presenting it as the sole prior prediction hides the selection process. Reporting it as exploratory and testing it independently makes the reasoning inspectable.

How should the unplanned subgroup finding be presented?As exploratory, with the search disclosed and independent testing proposedAs the only hypothesis predicted before seeing any outcomes

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