What is a frequency parameter?

Question

Mathematics

Reading the description of the NIST tests (tests for random number generators) I came across Sobs.
What does obs mean?

Answer 1

The abbreviation obs here is from observed, i.e. in Russian-language texts there should be something like Snab or Snab, i.e. some parameter computed for observed values ​​(also old-school saying "observed values"). According to the meaning of the formula, this parameter looks like dispersion.
Excuse: I studied mathematical statistics for a long time and remember almost nothing.