To simultaneously evaluate the decay constant of 40 K (λ) and the age of a standard (t std)
using isotopic data from geologic materials, we applied a series of statistical methods. The
problem of estimating the most probable intercept of many nonlinear curves in λ and t std
space is formulated by an errors-in-variables nonlinear regression model. Then a maximum
likelihood method is applied to the model for a point estimate, which is equivalent to the
nonlinear least square method when measurement error distributions are Gaussian …

To simultaneously evaluate the decay constant of 40K (λ) and the age of a standard (tstd)
using isotopic data from geologic materials, we applied a series of statistical methods. The
problem of estimating the most probable intercept of many nonlinear curves in λ and tstd
space is formulated by an errors-in-variables nonlinear regression model. Then a maximum
likelihood method is applied to the model for a point estimate, which is equivalent to the
nonlinear least square method when measurement error distributions are Gaussian …