Statements A, B, C and D correctly distinguish internal and external validity and the roles of random assignment and random sampling. Internal validity is about attributing effects to the treatment rather than confounds, while external validity is about generalising beyond the study context. Random assignment strengthens internal validity by equalising extraneous variables across groups, and random sampling supports external validity by making the sample more representative. Statement E is false because a study can have strong internal validity yet limited generalisability, so high internal validity does not guarantee high external validity.
Option A:
Option A is incomplete because it omits D, which correctly highlights the relation between random sampling and external validity. Without D, the link between sampling and generalisability is not fully represented.
Option B:
Option B leaves out statement A, overlooking the fundamental definition of internal validity as ruling out alternative explanations. Even though B and D address external validity and sampling, omitting A weakens the conceptual pair.
Option C:
Option C is correct because it includes all four accurate statements about internal and external validity and their methodological supports. It deliberately excludes E, which wrongly assumes that internal and external validity always go together. Thus this combination precisely reflects textbook distinctions.
Option D:
Option D is incorrect because it includes E, which overstates the relationship between internal and external validity, and it omits B, which defines external validity itself. This mixture of omission and error makes the option unacceptable.
Option E is also wrong because it incorporates E, the false automatic link between internal and external validity. A correct option must not contain this overgeneralisation.
Comment Your Answer
Please login to comment your answer.
Sign In
Sign Up
Answers commented by others
No answers commented yet. Be the first to comment!