Which statement best answers the question below. Despite the fact that the Black Death was widespread and deadly, it seemed that some Europeans were immune to it. it was not understood how it started or how it spread. it did not affect most countries in western Europe. it seemed that many doctors did not attempt to treat it.

Dr. robbins wants to know if there are different opinions regarding the value of public school education between native americans who have at least one relative who attended indian boarding school and native americans who have no family experience with indian boarding school. dr. robbins contacts 35 native american participants in each group. he wants each group to include younger as well as older adults, and a mix of male and female participants. he asks each person to complete a survey about their attitudes toward public education. the design of this study is: