How do I produce a line of best fit for graphs when I know the function they are supposed to map to?
Hello, I am currently writing up my laboratory report and I am stuck on what to do with my graphs. At the moment I have just produced a scatter graph, but I want to include a line of best fit so I can find which value corresponds to the 75% threshold.
The lines are supposed to map towards this equation:
Y = 100.0—(50.0*(2.0^(-((X/A)^B))))
However when running Opcode (which runs bootstraps in order to match the values in my graph to that equation) failed in all attempts.
I am using excel, but wouldn’t mind downloading something free in order to do the lines of best fits. If anyone could recommend some simple software I can use, I would be grateful. At the moment I am just using MS Excel which i’m not sure if the trend lines are valid (nor which one I am supposed to use).
P.S. The equation given should produce something that looks like:
Problems are that my graphs all look different: the first two appear to be around random and the rest look curved but barely anything like that.
If you need any more information, please ask as I am not sure what I need to give.
Appendix: The results of the 5 conditions (values of Y, X axis = 0.002 to 0.02; increasement of 0.002; 10 values total).
This question is in the General Section. Responses must be helpful and on-topic.