# How to combine two accuracy results?

If I am doing a machine learning experiment A and my accuracy lies in the interval of 0.8 +/-0.03 and I have a machine learning experiment B with an accuracy in the interval of 0.9 +/-0.1, how can I combine these two results into one? Are there any standard methods?

(The accuracy numbers I gave are for test sets that contain a sample of a whole population. However, these are two totally independent populations and samples.)

• just to be sure you are referring to accuracy with respect to a classification problem correct? Jan 8, 2016 at 20:01
• Yes, these are classification experiments. Edited the question. Jan 8, 2016 at 20:03
• statistical ensemble? en.wikipedia.org/wiki/Ensemble_learning Jan 8, 2016 at 21:52
• Thanks for the suggestion, @Mitch. What I am looking for is actually how to combine the results for reporting. So, I do not want to combine the classifiers or classification tasks, but rather, is there a way to calculate an overall accuracy for A and B? Jan 8, 2016 at 21:56

The combine accuracy depends on the proportions of A and B experiments. If we call the proportions of A and B experiments $\tau_A$ and $\tau_B$,
the combine accuracy is: $Acc = 0.8\times\tau_A + 0.9\times\tau_B$,
and the combine accuracy uncertainty is: $\delta Acc = \sqrt{0.03^2\times\tau_A^2 + 0.1^2\times\tau_B^2}$.