2. The concentration of chromium in a river was determined by means of atomic absorption spectroscopy at four different locations and three different depths at each location near an industrial waste disposal site. The results of analysis are summarized in the table below. Depth, m 0 0.5 1.0 1 50.0 46.0 45.0 Distance from site, km 2 3 30.5 20.2 30.4 18.0 27.5 15.0 4 10.3 8.0 6.0 Test whether there are significant variations in the chromium concentration (a) at different distances, and (b) at different depths