A university study examined the relationship between amount of sleep and school performance in college-age students. The Venn diagram represents the students who participated in the study. If A represents the students who slept more than 7 hours per night, and B represents the students who improved in school performance, what group of students does region C represent?

Question

anonymous · Answer

A. students who slept more than 7 hours per night and did not improve in school
B.  students who slept more than 7 hours per night and did improve in school
C.  students who slept exactly 7 hours and performed at the mean level for school performance
D. students who slept exactly 7 hours and did not improve in school

doc.brown · Answer

Do A and B overlap?  Is C that overlap?

anonymous · Answer

yes

doc.brown · Answer

If I am in A I sleep more than 7 hours.
If I am in B I improved in school performance.
If I am in C, I am in A and B, and therefore sleep more than 7 hours and improve in school performance.

It's a stupid question, right?  If I'm a student in B then I improve whether I sleep or not.

anonymous · Answer

OH! thank you!! I get so confused on this stuff