The filters installed contained a diffuser plate, fine sand, coarse sand, and gravel. Different filters had different amounts of sand that were split into two groups: filters with more than 2 inches of sand and filters with less than 2 inches of sand. Students recorded You will investigate the difference in E. coli counts when filtering the water with the two types of filters. In this sample, we have results from 19 filters, 14 with more than 2 inches of sand and 5 with less than 2 inches of sand.What are the explanatory and response variables and what type