Glossary » statistical validity
the degree to which an observed result, such as a difference between 2 measurements, can be relied upon and not attributed to random error in sampling and measurement.
The degree of statistical significance of a result depends upon the number of sampled data points (e.g. the number of users in a test), the size of the effect, and the amount of variation between measurements. Thus, statistical validity can be improved with increased samples, by reducing noise (and thus variation), and by creating as large an effect as possible.