Ecology: Wetlands Turbid water is muddy or cloudy water. Sunlight is necessary for most life forms;

thus turbid water is considered a threat to wetland ecosystems. Passive filtration systems are commonly used to reduce turbidity in wetlands. Suspended solids are measured in mg/L. Is there a relation between input and output turbidity for a passive filtration system and, if so, is it statistically significant? At a wetlands environment in Illinois, the inlet and outlet turbidity of a passive filtration system have been measured. A random sample of measurements follow

(Reference: EPA Wetland Case Studies).

Reading 1 2 3 4 5 6 7 8 9 10 11 12 Inlet

(mg/L) 8.0 7.1 24.2 47.7 50.1 63.9 66.0 15.1 37.2 93.1 53.7 73.3 Outlet

(mg/L) 2.4 3.6 4.5 14.9 7.4 7.4 6.7 3.6 5.9 8.2 6.2 18.1

(i) Rank-order the inlet readings using 1 as the largest data value. Also rank-order the outlet readings using 1 as the largest data value. Then construct a table of ranks to be used for a Spearman rank correlation test.

(ii) Use a 1% level of significance to test the claim that there is a monotone relationship (either way) between the ranks of the inlet readings and outlet readings.

AppendixLO1