Within the U.S. it is surprising that the average postal density of the bottom quartile of routes (ranked by cost) is lower than the postal density for the rural routes serving the least densely settled 10 percent of the population (50 versus 89).
The average postal density in rural areas is much less than in urban areas
mnli hypothesis: The average postal density in rural areas is much less than in urban areas premise: Within the U.S. it is surprising that the average postal density of the bottom quartile of routes (ranked by cost) is lower than the postal density for the rural routes serving the least densely settled 10 percent of the population (50 versus 89).