FIG. 3.

Operative stone burden across the state of California by county: Mean temperature and annual precipitation fitted model. The right panel reveals the actual county operative stone burden per 1000 persons. The left panel reveals the fitted prediction of actual county operative stone burden per 1000 persons based on the model of best fit (the table with the model is on the bottom). Note that the similarities in the maps, as the best fit model, including only precipitation and mean temperature, explain ∼35% of the variance in operative stone burden between counties.