What does it mean that a statistical result is reliable but not valid?
Correct Answer
A) It repeats consistently while measuring the wrong thing
Why this is correct: Reliability refers to the consistency or repeatability of a measurement. Validity refers to whether the measurement actually assesses the intended characteristic. A result can be consistently wrong if the model uses flawed data or measures the wrong variable. Why the other choices are wrong: 'It measures correctly but cannot be reproduced again' describes an unreliable but potentially valid measure. 'It applies to the population but not to the sample' misstates statistical concepts; reliability and validity are properties of the measurement itself. 'It was computed correctly but reported incorrectly' describes a reporting error, not a fundamental distinction between reliability and validity. Exam tip: Remember: Reliability is about consistency (repeatability); Validity is about accuracy (measuring the right thing).
Why This Is the Correct Answer
Why this is correct: Reliability refers to the consistency or repeatability of a measurement. Validity refers to whether the measurement actually assesses the intended characteristic. A result can be consistently wrong if the model uses flawed data or measures the wrong variable. Why the other choices are wrong: 'It measures correctly but cannot be reproduced again' describes an unreliable but potentially valid measure. 'It applies to the population but not to the sample' misstates statistical concepts; reliability and validity are properties of the measurement itself. 'It was computed correctly but reported incorrectly' describes a reporting error, not a fundamental distinction between reliability and validity. Exam tip: Remember: Reliability is about consistency (repeatability); Validity is about accuracy (measuring the right thing).
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