Measurement of Carbon-to-Iron Ratios (\[C/Fe\])
===============================================

Stellar Atmospheric Parameters
------------------------------

In order to derive the fundamental stellar atmospheric parameters ([$T_{\rm eff}$]{}, [$\log~g$]{}, and [\[Fe/H\]]{}) for the SDSS/SEGUE spectra, we employ the most recent update of the SEGUE Stellar Parameter Pipeline (SSPP; Lee et al. 2008a, 2008b, 2011; Allende Prieto et al. 2008; Smolinski et al. 2011). The SSPP processes the wavelength- and flux-calibrated SDSS/SEGUE stellar spectra, and delivers the three fundamental stellar parameters for most stars with spectral S/N ratio greater than 10 Å$^{-1}$, in the temperature range 4000–10,000 K. The SSPP estimates the atmospheric parameters through a number of approaches, such as a minimum distance method (Allende Prieto et al. 2006), neural network analysis (Bailer-Jones 2000; Re Fiorentin et al. 2007), and a variety of line-index calculations, which were calibrated with respect to known standard stars (e.g., Beers et al. 1999). This multiple approach permits the use of as wide a spectral range as possible, in order for the SSPP to obtain robust estimates of each parameter for stars over a wide range in [$T_{\rm eff}$]{}, [$\log~g$]{}, [\[Fe/H\]]{}, and S/N. The SSPP is able to determine [$T_{\rm eff}$]{}, [$\log~g$]{}, and \[Fe/H\] with typical external errors of 180 K, 0.24 