Question

Give an example of a lurking variable that might explain the nonsense correlation between time spent studying for an exam and grade received on the exam based on the scatterplot. Score on exam 100t Hours studying The lurking variable is "Current grade in the class." Students performing well in the class may not need to study long for exams. The lurking variable is "Study hours." The longer students study for the exam, the lower the grade they will receive on the exam. The lurking variable is "The Exam." Students should be given different exams based on the amount of time they spent studying. There are no lurking variables. Students should not study long for exams if they want to receive a high grade.

Answer 1

The lurking variable is "Current grade in the class." Students performing well in the class may not need to study long for exams.

Here the lurking variable is responsible for the nonsense correlation.

Students who perform consistently good in class may not need to study for many hours for the exam, while the last-minute studying students do if they have not performed well for the entire semester. But sometimes last-minute cramming is not enough for a high grade. Hence the lurking variable is current grade in the class.

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