Just under 25% of which group are in bed by 10:30 p.m.?

Which group has 100% in bed by 1:30 a.m.?

Which group has 50% of students in bed by 11 p.m. and then by 12 a.m. just over 75%?

Which group of students has the highest percentage of people in bed by 11:30 p.m.?

Which group of students has on average the most hours of sleep?