Answer:
This is a stratified random sample because a separate random sample is selected from each class
Step-by-step explanation:
Stratified random sampling is an appropriate method when the population consists of mixed characteristics and you would like to ensure that every characteristic is proportionally represented in the sample. In this example, the population is the students from Central High School and the mixed characteristics are the different classes such as Freshman students, Sophomore students, Juniors and Seniors.
After the population is divided into subgroups based on characteristics, from the overall proportion of the population, you calculate how many people should be sampled in each subgroup. Random or systematic sampling can then be used to select a sample from each subgroup.