Definition
Also known as “Standard Score”. The number of standard deviations by which the value of a raw score (i.e., an observed value or data point) is above or below the mean value of what is being observed or measured. – Wikipedia
CRO Example
The very, overly, simple version: a statistical measure of the difference between test variation samples. The larger the Z-score, the more certain you can be about the reported improvement in test result data. Proper application of a bell curve visualization makes it easier to understand and interpret. Here’s some additional reading that goes more in-depth and explains it much more thoroughly:
Additional reading
- Definition, Formula & Calculation – Statistics How To
- Be a Statistically Significant Marketer (Part 2) – Marketing Land