Answer: random sampling
Explanation:
- In statistics, a random sample refers to a subset of the population surveyed by the researcher , selected in a way such that all the individuals in the population has an equal probability to get selected.
Given : To determine customer opinion of their check dash in service, American Airlines randomly selects 70 flights during a certain week and surveys all passengers on the flights.
Here probability for each flight to get selected is equal.
Therefore, a random sampling is used here.