Answer
a. Systematic
b. Random
c. Cluster
d. Stratified
e. Convenience
Work Step by Step
a. This is systematic sampling, for every nth person (in this case, every 150,000th person) is chosen.
b. The choice is random, so this is random sampling.
c. This is cluster sampling, for the population of the study is turned into clusters, and people from each cluster are chosen.
d. This is stratified sampling, for there are 150 regions, and 10 people are randomly chosen from each one.
e. This is convenience sampling, for who is selected is based on who chooses to respond to the survey.
