Beginners Guide to Maths and Stats behind Web Analytics (opens in new tab)

This question doesn't have a clear answer, because the values are already percentages. Imagine the original numbers refer to apples. First there were 10 apples, then 12 apples. The absolute increase is 2 apples; the relative increase is 20%. Obviously, if you say "the increase is __ apples" or "the increase is __ %" there's only one right way to replace the blanks with numbers. But since 10 and 12 are already percentages, the absolute and relative changes would be stated as "the increase is 2%" (absolute increase) and "the increase is 20%" (relative increase.) They mean different things, but they're both correct statements if interpreted correctly.

In practice, people will expect one and interpret the other as wrong. Knowing which one they expect is not a matter of statistics.

                signal
   confidence = ------  x  \sqrt(sample size)
                noise
                

Edit: corrected despair-induced typos.

What surprise me, that it doesn't get attention it deserves at pre-university education. A lot of lessons in math are about geometry, algebra, etc. which are a great way to learn logical and abstract thinking, but aren't as useful as statistics.

Feel free to ping me if you need help getting started (or a longer trial :)

Here's a simple example for unique visitors by month:

    SELECT
    YEAR(dt),
    MONTH(dt),
    COUNT(DISTINCT(user_id))
    FROM events
    GROUP BY YEAR(dt), MONTH(dt) ;