In Exercises 9–20, identify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster. Driving A student of the author conducted a survey on driving habits by...

In Exercises 9–20, identify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster.

Driving A student of the author conducted a survey on driving habits by randomly selecting three different classes and surveying all of the students as they left those classes.