While surfing the internet, I found a prize Claim Form from Tim Hortons (Coffee Shop). It requires the winners to complete a skill test, a simple arithmetic exercise, to claim the prize (link). The exercise goes like this: multiply 2×4, add 8, subtract 4, add 6 and then show the correct answer. The exercise is unrelated to the quality or value of the prize but a requirement for receiving the prize.
It reminds me of F2 (similarity factor) requirement. It is a very similar arithmetic exercise as well, with added parameters of taking the logarithm and square root of numbers to come up with an answer to receive the “prize” of “regulatory compliance”, i.e., regulatory approval of your product (usually tablet/capsule) as bioequivalent with or without a human bioequivalence study. The point is the skill test, in this case, the “similarity factor” unrelated to the product quality (scientifically, statistically, or otherwise) and/or lacks relevance to the human bioequivalence study but is required to meet a compliance requirement (link).
By the way, suppose you would use a scientific calculator or computer spreadsheet for the calculations. In that case, you might also be required “validation” the calculator and spreadsheet software to confirm that they or you are performing proper calculations, for which one might require the help of a CSV (Computer Software Validation) expert or consultant.
The F2 (similarity factor) is an invention of the FDA for regulatory compliance. Otherwise, one does not have to worry about this factor as this is a useless exercise unrelated to the quality of the pharmaceutical products.