Answer:
The kind of sample is Dr. Simpson using is: cluster random sample.
Explanation:
Cluster random sample is about dividing the sample of the chosen population, into separate groups called clusters. So the total sample, which is the opinions favoring/opposing federalized healthcara among adults living in citys of a specific number of people, is divided in clusters. Which in this case are: differnt cities with the amount of people stablished, then 10 selected census tracts from the 10 cities selected, and then selects the blocks of those census tracks.