According to the U.S. Census Bureau, the county has a total area of 685 square miles (1,770 km2), of which 681 square miles (1,760 km2) is land and 3.8 square miles (9.8 km2) (0.6%) is water. It is the fourth-largest county in Tennessee by area. The county is located atop the Cumberland Plateau.
Revenue passenger kilometres (RPK) is a measure of the volume of passengers carried by an airline. A revenue passenger-kilometre is flown when a revenue passenger is carried one kilometre. A passenger for whose transportation an air carrier receives commercial remuneration is called a revenue passenger.
In my last column, I was asked about a capability index called Cpk. Cpk is a measure of a process' ability to conform to specification. A Cpk = 1 means that if nothing changes, 99.73% of the process output will be within specification, as in Figure 1. Figure 1 - A process with Cp = Cpk = Cpm = 1.