A supplemental Matlab function “ftest” is included with the manuscript
Anderson and Conder, 2011, Discussion of Multicyclic Hubbert modeling as a method for forecasting future petroleum production, Energy and Fuels, dx.doi.org/10.1021/ef1012648.
This function uses a statistical F-test to determine the likelihood that an observed improvement of a fit to data warrants the use of additional parameters. The function was written in Matlab ver. R2010b (Mac). The “.txt” extension is for ease of distribution and should be removed for use.
>> [ p ] = ftest(n,np1,np2,chi1,chi2)
The function requires five inputs: n is the number of data to be fit. np1 & np2 are the numbers of free parameters used in the two models. chi1 and chi2 are (normalized) sums of the squares of the misfits to the data for the two models.
One output, p, is returned. p is the probability (between 0 and 1) that the improvement of the fit is due to chance. Therefore a small value of p means a high confidence that the additional parameters are warranted.
March 10, 2011