Comment by necovek

I mean, sure you could test over only part of the day, but if you do, that is, imho, bad math.

Eg. I could sum up 10 (decimal) and 010 (octal) as 20, but because they were the same digits in different numbering systems, you need to normalize the values first to the same base.

Or I could add up 5 GBP, 5 USD, 5 EUR and 5 JPY and claim I got 20 of "currency", but it doesn't really mean anything.

Otherwise, we are comparing incomparable values, and that's bad math.

Sure, percentages is what everybody gets wrong (hey percentage points vs percentage), but that does not make them not wrong. And knowing what is comparable when you simply talk in percentages, even more so (as per your examples).