“Observed power”, “Post hoc Power”, and “Retrospective power” all refer to the statistical power of a statistical significance test to detect a true effect equal to the observed effect. In a broader sense these terms may also describe any power analysis performed after an experiment has completed. Importantly, it is the first, narrower sense that […] Read more...| Blog for Web Analytics, Statistics and Data-Driven Internet Marketing | Analy...
The above is a question asked by some practitioners of A/B testing, as well as a number of their clients when examining the outcome of an online controlled experiment. It may be raised regardless if the outcome is statistically significant or not. In both cases the fact the observed effect in an A/B test is […] Read more...| Blog for Web Analytics, Statistics and Data-Driven Internet Marketing | Analy...
Observed power, often referred to as “post hoc power” and “retrospective power” is the statistical power of a test to detect a true effect equal to the observed effect size. “Detect” in the context of a statistical hypothesis test means to result in a statistically significant outcome. Some calculators aimed at A/B testing practitioners use […] Read more...| Blog for Web Analytics, Statistics and Data-Driven Internet Marketing | Analy...
Navigating the maze of A/B testing statistics can be challenging. This is especially true for those new to statistics and probability. One reason is the obscure terminology popping up in every other sentence. Another is that the writings can be vague, conflicting, incomplete, or simply wrong, depending on the source. Articles sprinkled with advanced math, calculus equations, and poorly-labeled graphs represent a major hurdle for newcomers.| Blog for Web Analytics, Statistics and Data-Driven Internet Marketing | Analy...
Running shorter tests is key to improving the efficiency of experimentation as it translates to smaller direct losses from testing inferior experiences and also less unrealized revenue due to late implementation of superior ones.| Blog for Web Analytics, Statistics and Data-Driven Internet Marketing | Analy...
One topic has surfaced in my ten years of developing statistical tools, consulting, and participating in discussions and conversations with CRO & A/B testing practitioners as causing the most confusion and that is statistical power and the related concept of minimum detectable effect (MDE). Some myths were previously dispelled in “Underpowered A/B tests – confusions, myths, and reality”, “A comprehensive guide to observed power (post hoc power)”, and other works. Yet others remain.| Blog for Web Analytics, Statistics and Data-Driven Internet Marketing | Analy...
Suppose I tell you that only 1% of people with COVID have a body temperature less than 97°. If you take someone's temperature and measure less than 97°, what| Life Is Computation