Spectroscopy of Luminous Infrared Galaxies at 2 Microns. III. Analysis for Galaxies with log (<i>L</i>_IR/<i>L</i>_☉) ≳ 11.2

We have obtained spectra across the K window for the first large sample of luminous galaxies selected from the IRAS survey. This paper contains the principal analysis of the 43 systems in our sample with luminosities of 11.2 ≲ log (LIR/L☉) ≲ 11.9. The spectra themselves were presented in a companion paper by Goldader et al. (Paper II).