A study looked into the management of various tropical grasses for improved production, measured as dry matter yield in hundreds of pounds per acre over a 54-week study period. The management variables were height of cut (1, 3, or 6 inches), the cutting interval (1, 3, 6, or 9 weeks), and amount of nitrogen fertilizer (0, 8, 16, or 32 hundred pounds of ammonium sulfate per acre per year). Forty-eight plots were assigned in completely randomized fashion to the 48 factor-level combinations. Dry matter yields for the plots are shown in the table below (data from Richards 1965). Analyze these data and write your conclusions in a report of at most two pages.
