Having discovered that most student passengers on the Porter Ottawa–Toronto route
use the free internet service in the airport lounges (see For Example: “Observational
studies for Ottawa–Toronto f lights”), you decide to find out how best to attract
more students to f ly the route. After purchasing a mailing list of 16,000 students,
you decide to randomly send one-quarter a coupon worth 10% off their next trip
(Coupon), one-quarter a bonus card (Card), and one-quarter a free Netf lix download
during their next trip (Movie). The remaining 4000 students will receive no offer (No
Offer). You plan to monitor the four groups to see which group travels most during
the 12 months after sending the offer.
QUESTION: 

What kind of study is this, an observational study or an experiment?
What are the factors and levels? What are the subjects? What is the response variable?