The U.S. legal/statistical areas, their median household income, and a matrix of knots provided only to facilitate illustrative examples.
data(countyExample)
countyExample contains 3 objects:
A SpatialPolygonsDataFrame containing 3109 areas. For each areal unit, the following data are defined
A 3109x2 matrix containing the public-use American Community Survey (ACS) 2013 5-year estimated county-level median household income and its variance.
A 75x2 matrix of knots spanning the county data.
U.S. Census Bureau. 2013-2017 American Community Survey 5-year Estimates; generated by Jonathan Bradley; using American FactFinder.