Error on calculator for error of bound fraction

[carandraug]

The equation to caclulate the error of the bound fractions is wrong

BdFr_sigma = ((koff_sigma/koff_average)+((kon_sigma+koff_sigma)/(kon_average+koff_average))) * BdFr_average;

it should be

BdFr_sigma = ((kon_sigma/kon_average)+((koff_sigma+kon_sigma)/(koff_average+kon_average))) * BdFr_average;