Abstract: In various example embodiments, systems and methods for estimating the mean of a dataset having a fat tail. Data sets may be partitioned into components, a “torso” component and a “tail” component. For the “tail” component of the data set a more efficient estimator can be obtained (versus the traditionally calculated mean) by using the tail data to estimate parameters for a specific distribution and then deriving the mean from the estimated parameters. The estimated mean from the torso and the estimated mean from the tail may then be combined to obtain the estimated mean for the full data. This can be applied to gross merchandise bought (GMB) by various samples of visitors and apply the experience that was provided to the sample with the highest GMB to all visitors to increase gross revenue.