Fig. 4: Results of the radiometric regression analysis on the Tupiguarani dataset.

Top: Bivariate plot of age versus distance from chosen origin, showing the calibrated radiometric densities (grey curves), the result of the quantile regression to 99th-percentile when using median dates (red line), the spread of regressed lines when taking the full radiometric uncertainty into account (blue-shaded region), and the confidence envelope of the null hypothesis of no-dispersal (grey-shaded region with dashed border). Bottom Left: Summed probability density of obtained y-intercept regression parameter for the empirical dataset (blue curve), confidence envelope of the null hypothesis of nodispersal (grey-shaded region), best estimate and corresponding 95% range when doing regression with median dates (red dot and bar). Bottom Right: Summed probability density of obtained slope regression parameter with the same key as the previous panel.