systematic effects caused by systematic uncertainties in the photometric redshift estimates are quantified. The results are summarized in § \[sec-disc\]. We assume $\Omega_{\rm M}=0.3$, $\Omega_{\rm \Lambda}=0.7$, and $H_{\rm 0}=70$ km s$^{-1}$ Mpc$^{-1}$ throughout the paper. All magnitudes are on the AB system.

SAMPLE SELECTION {#sec-ss}
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The NEWFIRM Medium Band Survey
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The sample is selected from the NMBS, a moderately wide, moderately deep near-infrared imaging survey [@vandokkum09b]. The survey uses the NEWFIRM camera on the Kitt Peak 4m telescope. The camera images a 28$^{\prime} \times$28$^{\prime}$ field with four arrays with a native pixel size of 0$^{\prime \prime}$.4. We developed a custom NIR filter system for NEWFIRM, comprised of five medium bandwidth filters in the wavelength range 1 $\mu$m–1.7 $\mu$m. As shown in @vandokkum09b, these filters pinpoint the Balmer/4000 Å  breaks of galaxies at $1.5<z\lesssim3.5$, providing accurate photometric redshifts and improved measurements of the stellar population parameters. The survey targets two 28$^{\prime} \times$28$^{\prime}$ fields: a subsection of the COSMOS field [@scoville07], and a field containing part of the AEGIS strip [@davis07]. Field positions and other information are given in @vandokkum09b. Both fields have excellent supporting data, including extremely deep optical $ugriz$ data from the CFHT Legacy Survey[^1] and deep Spitzer 