Goodness-of-fit as a function of a fixed parameter 𝒜_i, while letting the remaining parameters vary freely. The red circle marks the best-fit value (𝒜_BF as determined from the genetic-simplex method). The dashed line marks the value of defined in Eq. (8). The intersection of with the blue points defines the 1σ confidence interval for the parameter 𝒜_i (see the results in Table 2). Orange circles correspond to chaotic orbits, with 〈Y〉 ≳ 2.1 (see the text).