Origin uses the F-Test to find the best model for one dataset.
Suppose the residual sum of square and degree of freedom for the two fit result is , we have:
We can combine the two data sets (appending one to the other), and then perform a fit on the combined data set with the same function and calculate the residual sum of square and degrees of freedom, which are denoted as and . Then we can compute the F value by:
Once the F value is computed, Origin calculates a p-value by:
This p-value is then used to make a statistical statement as to whether or not the data (not the parameter values) are significantly different. If the p-value is greater than 0.05, we can say that the datasets are not significantly different at the 95% confidence level.