Final answer:
The sampling method used is stratified sampling, which divides the population into distinct subgroups and selects a sample from each subgroup.
Step-by-step explanation:
The sampling method used to determine customer satisfaction with their service department, an automobile dealer randomly selects 20 hybrid-vehicle owners, 20 SUV owners, and 20 sedan owners, is stratified sampling.
Stratified sampling is a method in which the population is divided into distinct subgroups or strata, and then samples are randomly selected from each subgroup. In this case, the dealer is dividing the owners into three groups based on the type of vehicle owned (hybrid, SUV, and sedan) and selecting a sample from each group.
This method ensures that each subgroup is represented in the sample, allowing for more accurate insights into customer satisfaction for each specific vehicle type.