## So the final equation of line becomes y = mx + b:

(%Response-Median) = 63.7495854(LOG Dose) + (-59.85831)

So to solve for the value of LOG Dose fo which we have 50% response we set y=0 above to get:

0 = mx + b, or x = -b/m

x = 0.93896861

But x is LOG Dose so to get Dose we must take 10 to the power of x:

10 to power x = 8.68897627

This says that at a dose of 8.7 there will be 50% response.

9:1