9.8 California water (Data file: water) Draw residual plots for the mean function described in Problem 8.3.4 for the California water data, and comment on your results. Test for curvature as a function of fitted values. 9.7 PROBLEMS 229 Table 9.4 Crustacean Zooplankton Species Data (Dodson, 1992) Variable Description Species Number of zooplankton species MaxDepth Maximum lake depth, m MeanDepth Mean lake depth, m Cond Specific conductance, micro Siemans Elev Elevation, m Lat N latitude, degrees Long W longitude, degrees Dist Distance to nearest lake, km NLakes Number of lakes within 20 km Photo Rate of photosynthesis, mostly by the 14C method Area Surface area of the lake, in hectares Lake Name of lake