Re: calcuating goodness of fit in the statistical tool box

Jing Cao wrote:

the fitting, can I use the loglikelihood as an indicator for
comparing my models? (I used normal, lognormal, and Weibull
for the same dataset - the results are more or less
similar, but I still want to rank the results with some kind
of indicator of the fit).

Those are alltwo-parameter models, but none is a special case of the others. So while technically, you should not be using a likelihood ratio test, you could compute the AIC using the log-likelihoods.

However, I don't recommend doing (only) that. A single number cannot possibly tell you why/how a model doesn't fit as well as another. If you're already using DFITTOOL, take the opportunity to make plots of the PDF against the data, or better yet, CDFs or probability plots. Look and see _how_ the various model do or don't fit the data -- skewness? heavy tails? and so on. Decide whether any discrepancies are important or not.

Hope this helps.
.

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