The index of biotic integrity (IBI) was used to measure the water quality in streams and land-use measures for collecting streams in the Ozark Highland ecoregion of Arkansas. The data table below provides the data for IBI, the percentage of the watershed that was forested, and the area of the watershed in square kilometers for streams in the original sample with a watershed area less than or equal to 70 km2.
Area Forest IBI
E 55 10
25 33
18 100
100