The table shows the public medical expenditures (in billions of dollars) for workers' compensation x, Medicaid y, and Medicare z from 2005 through 2010.

A model for the data is given by

(a) Find

(b) Determine the concavity of traces parallel to the xz-plane. Interpret the result in the context of the problem.

(c) Determine the concavity of traces parallel to the yz-plane.
Interpret the result in the context of the problem.

Transcribed Image Text:

Year 2005 X y N 2006 2007 2008 2009 36.7 37.2 374.4 401.4 524.6 41.2 41.6 41.2 309.5 306.8 338.8 403.1 326.4 40.1 343.8 432.3 466.9 499.8 2010