With the use of biofuels increasing, investigators are looking for ways in which the wood ash that is a byproduct of biomass combustion can be used. An experiment described in the paper "Wood Ash Ad mixture to Organic Wastes Improves Compost and Its Performance" (Agriculture, Ecosystems & Environment [2008]: 43-49) looked at the effect of using wood ash in compost. Composts with 0%, 8%, and 16% ash were applied to plots in an experimental field. The plots were grouped into four blocks to create blocks that consisted of plots with similar soil characteristics. Treatments (the three composts) were assigned at random to the plots within each block. At the end of the composting period, the concentration of lead (mg/kg) was measured. Use the accompanying data (consistent with summary quantities given in the paper) to determine if there is evidence that the mean lead concentration differs for the three ash concentrations. Use a = 0.01.

Block 0% Ash 8% Ash 16% Ash 61.4 39 34.7 57.2 41 38.2 A W N - 58 38.5 34.7 63.5 40.3 33.4