Answer: N
An observational study showed that students who got less than 8 hours of sleep performed worse on exams than students who got 8 hours or more of sleep. Can we make a cause-and-effect conclusion?A) Yes.B) No.

Ludwig Josef Johann Wittgenstein (/ ˈ v ɪ t ɡ ən ʃ t aɪ n -s t aɪ n / VIT-gən-s(h)tyne; German: [ˈluːtvɪç ˈvɪtɡn̩ˌʃtaɪn]; 26 April 1889 – 29 April 1951) was an Austrian-Briti...