I am trying to fit a power curve into my data with the following gnuplot code.
f(x) = a*x**b;
fit f(x) 'data.txt' u 2:4 via a,b
plot 'data.txt' u 2:4 w l, f(x) w l
The estimate value of a and b seems to be good, however the plot is strange. I tried to set appropriate initial values for a and b but I have the same problem.
Here is my data file http://s000.tinyupload.com/?file_id=09032867895093746864
Thanks a lot