i need help with b-h please

2. Be Sure to Get Your Beauty Sleep! New research supports the idea that people who get a good night's sleep look more attractive. In the study, 23 volunteer subjects ages 18 to 31 were photographed twice, once after a good night's sleep and once after being kept awake for 31 hours. Hair, make-up, clothing, and lighting were the same for both photographs, and the order of the two treatments was randomized for each subject. Observers then rated the photographs on a scale of 1 to 10 for attractiveness, and ratings under the two conditions were compared. The researchers report in the British Medical Journal that "Our findings show that sleep-deprived people appear less attractive compared with when they are well rested." (a) What are the cases in this study? (b) What is the explanatory variable? Is the explanatory variable quantitative or categorical? (c) What is the response variable? Is the response variable quantitative or categorical? (d) Is this (i) an observational study, (ii) a randomized comparative experiment, or (iii) a matched pairs experiment? Justify your answer. (e) Was the sample selected at random from the population? (yeso) (f) Was the explanatory variable randomly assigned? (yeso) (g) Can we generalize the result to the population? (yeso) Explain. (h) Can we establish causality from this study? (yeso) Justify