For each of the following, state whether you'd use one-sample or two-sample procedures to analyze the data, and explain why.

a. a university is interested in whether there's a difference between students who live on campus and students who live off campus with respect to absenteeism. over one semester, researchers take random samples of on-campus and off-campus students and record the number of classes each student misses. (1 point)
b. a company wants to know whether listening to music improves efficiency among its employees. two employees are randomly chosen from each of 10 departments and are given the same task to complete. one employee from each pair is allowed to listen to music and the other employee isn't. researchers record the time it takes each employee to complete the assigned task. (1 point)
c. a restaurant owner wants to know whether customers will drink more coffee if he switches to a new brand. every night for one week, he randomly selects one half of the restaurant and serves the new brand to customers who sit in this section. customers in the other half receive the old brand. he records the number of refills ordered in each section. (1 point)
d. you want to know if there's a difference between the time it takes you to get to school on the bus and the time it takes you to get to school when you get a ride from a friend. over a semester, you flip a coin to decide whether you'll take the bus or get a ride. you record your travel time daily.