How to insert TD50 equation in GraphPad

Dear all,

i was trying to calculate the TD50 for my survival analysis but i am messed up somehow the way to define it in GraphPad…

Most literature illustrate the equation as follows:
Y = Bottom + [Top − Bottom]/[1 + 10(log EC50 − X)(Hill slope)],
where X is the logarithm of days, Y is the average of dead worms (3), and EC50 is the midpoint of the curve.

I have attached my GrapPad analysis here and hope if someone may help me out. Appreciate that!
Here is my dropbox link to the graphpad file


Hi Tyrael,

Actually, GraphPad has that equation built in :smiley: It’s called Sigmoidal dose-response (variable slope).

Insert → New Analysis → Non-linear regression → Sigmoidal dose-response (variable slope)

I cloned the equation and entered the new/edit mode of the equation editor so you can see it:

Oh my god! It’s just within a click!
Snug, you have just saved my day! Thank you so much!!! :smiley: ;D