Scientific Results, Volume 181 L.D. Millwood et al., Ms 181SR-208 Table ATD3. Carbonate model parameter estimates, Site 1121. Note: FD = first derivative of the spectral value, DF = degrees of freedom. Variable DF Parameter estimate Standard error t value Probability > |t| Intercept 1 -5.620012 0.42901373 -13.1 0.0001 R1 1 0.16317 0.03494793 4.669 0.0003 FD4 1 1.135263 1.75661072 0.646 0.5279 FD7 1 -0.763586 1.41667175 -0.539 0.5978 FD21 1 -1.828062 1.15902038 -1.577 0.1356 FD30 1 0.220452 1.61975973 0.136 0.8936