Angel Hotel Group shares its customer information with Google so that whenever a user is using Google's search engine, the hotel would know whether the user is a registered customer at the hotel. Suppose the hotel's marketing department mainly targets the hotel's registered customers that are searching for travel related keywords such as "hotel" on Google. For each regis- tered customer /, let X, = 1 if the customer is searching for a travel-related keyword and X, = 0 if otherwise. For each registered customer doing a travel-related search, the hotel Is able to win the bid to push its ads to the customer with a probability of 40. For those registered customers not searching for travel-related keywords, they see the hotel's ads with a probability of 5% through internet traffic outside Google. From Google Ad's analyt- ics data, the proportion of registered customers' searching for hotels on Google is about 20%%. Let W, 6 {0, 1) denote a registered customer's treatment assignment such that W/ = 1 means the customer sees the hotel's ad whereas W, = 0 when the customer does not see the hotel's ad. Let Y, 6 {0, 1) be the observed outcome where Y, = 1 if the customer / makes a booking and Y, = 0 if otherwise. Each customer / is associated with the two potential outcomes Y,(0)