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CARD 01 · Scientific Investigation
What changes when volunteers are randomly assigned to conditions?
Reveal answer & explanation
Placement within the enrolled sample becomes random, reducing systematic pre-existing group differences in expectation. Recruitment is still voluntary.
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Original foundation lessons and 48-question MCQ practice across selected goals; not complete CED coverage..
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These prompts and explanations are the site's original learning materials. The reference links below support the selected skills; they are not endorsements or official examination questions.