four-parameter logistic equation
Not sure what your are asking of Solver. Do you have a set of (x,y) data
that need to be fitted to the stated equation?
Possible worksheet starting in A1
top 1 (some starting guesses)
x y y(calc)
1 23 99
2 34 104
Let the parameters be in B1:B4
Let the X's be in A10:A50, Y's in B10:B50 and Y(Calc) in C10:C50
The y(calc) values come from your formula
In another cell Say B5 enter this formula
DevSq = SUMXMY2(B10:B50, C10:C50)
Have Solver minimize the value in B5 by varying B1:B4
Now you should have a fairly good agreement between Y and Y(calc)
I would invite you to email me the file but I am off on vacation this
> I am having problems trying to get Excel to do a four-parameter
> logistic equation using the solver add-in.
> y=Bottom + ((Top - Bottom) / (1+ 10(logEC50-X).HillSlope))
> Can anyone tell me if I am asking too much of Excel.
> I have some values got from a curve fitting program (Prism) but when I
> pull them into my equation the curve is no where near the orginal raw
> Any suggestions will be useful