1. An automated testing system comprising: one or more processors; one or more memories; and computer instructions, stored on a physical data storage device within the automated testing system that control the automated testing system to process stored test results using a robust method, which generates and uses ranks of test-result values, to identify one or more particular single-factor variants or multi-factor/multi-level variants that produce test-result distributions different from one or more other test-result distributions; for one or more of the identified variants, process stored test results to determine expected results and one of confidence intervals and significance levels, the processing to determine one of confidence intervals and significance levels including determining, by computing only a fraction of the computed values in a virtual sorted array of values computed from possible pairs of a set of initial values, a computed value stored in a particular element of the virtual sorted array associated with a particular index; and store an indication of one or more of the one or more identified particular variants and one or more of the one of determined confidence intervals and determined significance levels in a physical data-storage device.