Weightening and fitting
Thu, 07/15/2021 - 10:28 am
It’s the first time I use Igor software and I have some doubts about curve fitting.
I have 12 datapoints in triplicate that I got by an FP assay. I calculated average values and standard deviation by using excel spreadsheet.
I used Igor in two ways and I don’t know if they are correct.
1) I loaded x values, average values and standard deviation in a table. I plotted average data vs x values, I modified the points by adding error bars and selecting the column containing my standard deviations as source of positive y and negative y for error bars. Then I fitted by Hill-curve but I did not selected nothing in “weighting”. I got an xhalf = 210 +- 99 and a V_chisq ⁓ 10E-06
2) I did the same things but I did not select “none” as weighting, I selected the column with my standard deviations and barred the “standard deviation” box. I got xhalf= 153.2 +- 119 and Vchisq = 2.44072.
I did not well understand the meaning of weighting and Vchisq. I would think the first way is better (and so I shouldn’t have had to weight the fitting ) if Vchisq was chi square.
I hope you can help me and I thank you in advance,