Statistical Methods for Analyzing Speedup Learning Experiments

Speedup learning systems are typically evaluated by comparing their impact on a problem solver's performance. The impact is measured by running the problem solver, before and after learning, on a sample of problems randomly drawn from some distribution. Often, the experimenter imposes a bound on the CPU time the problem solver is allowed to spend on any individual problem. Segre et al. (1991) argue that the experimenter's choice of time bound can bias the results of the experiment. To address this problem, we present statistical hypothesis tests specifically designed to analyze speedup data and eliminate this bias. We apply the tests to the data reported by Etzioni (1990a) and show that most (but not all) of the speedups observed are statistically significant.