Initial parameter dialog incremental data

If you choose to fit a Richards curve to incremental data, Growth II will ask you to enter an appropriate value for the parameter that fixes the point of inflection.

If you do not want a value of 0.5 (the default) click on the number and type in the required number. This dialog gives you some guide values - for example, if a value of 1 is entered you will in fact be fitting the Gompertz. It is worthwhile examining the shape of your curve to decide if the shape is closer to a logistic von Bertalanffy or Gompertz in shape and then chose a shape parameter value close to that of the appropriately shaped curve.