Xavier Fok

Standard deviation is the single number for how far your values sit from their average. Here is what it measures, the rough rule you can lean on, and the traps.

A plain-English guide to picking an analytics baseline that holds up under scrutiny, with the traps solo operators fall into and how to avoid them.

A confidence interval is the honest way to show a number as a range instead of a single false point. Here is what the range and its confidence level mean, and how to read yours.

Sample size is the count of events behind a number. Here is why a small one is mostly luck, what really drives how much you need, and the honest answer for a business of one.

My active customer count jumped 19 percent overnight because I had edited one line of a query eleven days earlier and forgotten. A metric definition with no effective date turns your own history into a rumour.

A moving average smooths a jagged daily number into a readable trend. Here is how to pick the window, why it lags, and the traps that fool a solo founder.

Vanity metrics only ever go up and change no decision. Here is how to spot them, turn totals into honest rates, and keep the numbers that actually matter.

At forty customers a monthly churn rate can only take four values, and the distance between healthy and alarming is one person. Four standard metrics that go from imprecise to actively misleading once the denominator gets small.

The mean adds everything up; the median takes the middle. Here is why a few big customers make the average lie, and which one to trust when.

A practical look at where AI genuinely speeds up analytics for solo founders in 2026, where it quietly gets things wrong, and how to use it without handing over your judgment.