Dinosaurs: confidence intervals

A last thing to check are the confidence intervals around your trend line. Unfortunately, Tableau can't calculate confidence intervals for a power model. Remember that a power model fits best on two variables that both have a logarithmic trend. Therefore, the new workbook you're about to open now contains the transformed, natural logarithms of mass and femur length. As a result, mass and femur length will show a linear trend. Consequently, you can plot the confidence intervals again.