**Applying and Exploring Bayesian Hypothesis Testing for Large Scale Experimentation in Online Tutoring Systems**

*Vijaya Dommeti and Douglas Selent*

This paper demonstrates the viability of using Bayesian hypothesis testing for statistical analysis of experiments run in online learning systems. An empirical Bayesian method for learning a genuine prior from past historical experiment data is applied to a dataset consisting of twenty-two randomized controlled A/B experiments collected from the ASSISTments online learning platform. We show that using only twenty-two experiments results in a learned genuine prior with poor confidence interval estimates, and that roughly 200 experiments are required for a reasonable estimate of the true probability of an experiment having differences between experiment groups. We also conducted a leave-one-experiment-out cross-validation experiment, where a genuine prior is learned from twenty-one of the randomized controlled experiments provided in the dataset and then used to evaluate the remaining experiment. From this experiment we show that Bayesian hypothesis testing performs similar to Frequentist hypothesis testing and both methods were in agreement.