**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*