A random sample of boarding school students was asked how many 8-ounce servings of soda they had consumed on a certain Sunday and how many hours of sleep they got that night. Their responses are displayed in the scatter plot below.

a) What is the correlation between the number of soda servings and hours of sleep?
b) How many students consumed more than 4 servings of soda?
c) How many students slept for more than 8 hours?
d) What is the average number of soda servings consumed by students who slept for 7 hours?