Guides & How-tos · Worked examples · Real numbers

Statistics guides

Step-by-step how-tos, head-to-head comparisons and honest roundups — every guide worked through with current figures, then backed by a RECATOOLS calculator or AI-directory entry so you can act on it.

498 guides published 17 topic areas Latest guide Oct 2026

All 498 Developer Tools 68 AI & ML 63 Finance 52 Home & Living 46 Chinese Culture 43 Statistics 33

A row of terraced front doors along a stone street, one of them painted a bright purple that stands out from its neighbours

Statistics 5 min

What Happens When You Test Twenty Metrics

A dashboard rarely shows one number. Simulated with nothing real to find, examining twenty metrics produced at least one...

Nadia Rahim

Pub. 24 Aug

A wooden scoop pouring green coffee beans back into a large open sack

Statistics 5 min

How Big Does an A/B Test Need to Be?

Sample size is usually decided by how long someone will wait. Simulated across a grid, a genuine one-point lift on a ten...

Nadia Rahim

Pub. 23 Aug

A young seedling with a few leaves growing from bare soil, against a blurred green background

Statistics 5 min

What Happens When You Check an A/B Test Early

Twenty thousand simulated experiments with no real difference in them. Read once at the end, 4.9% came back significant,...

Nadia Rahim

Pub. 23 Aug

Overhead view of a student writing on an exam paper at a desk.

Statistics 9 min

Grades, GPAs and What They Convert To

NUS publishes separate grade profiles for A-level and polytechnic applicants, and none at all for IB — because, it says,...

Nadia Rahim

Pub. 1 Aug

A close-up image showcasing uncooked rice grains in a wooden scoop on a textured dark surface.

Statistics 12 min

Kati, Tahil, Cups and Grams

Ask for a catty of pork and you get 500 g in Guangzhou, 600 g in Taipei and 604.8 g in Singapore — all three legally cor...

Nadia Rahim

Pub. 1 Aug

Dense Kuala Lumpur housing at blue hour, lit windows against a deep navy sky.

Statistics 15 min

Mean, Median, Mode: The Average Is a Choice, Not a Fact

Three different numbers are all correctly called "the average", and which one gets published changes what a reader concl...

Nadia Rahim

Pub. 26 Jul

Graph paper under a desk lamp with a hand-inked cloud of dots and a brass magnifier, no axes or numbers.

Statistics 20 min

A High R² Does Not Mean the Model Is Right

Anscombe printed one regression summary for four data sets in 1973 and said the features that matter are "invisible if w...

Nadia Rahim

Pub. 26 Jul

Dozens of identical freshly machined brass flanged parts stand in rows on a workbench.

Statistics 17 min

Standard Deviation vs Standard Error: Two Numbers, Two Questions

Mean ± 4.36 and mean ± 0.97 are not two ways of saying the same thing. Altman and Bland assigned each to a different que...

Nadia Rahim

Pub. 26 Jul

A survey interviewer with a clipboard stands at a lit doorway at the end of a dim corridor.

Statistics 17 min

What a 95% Confidence Interval Actually Means

Nearly everyone reads a confidence interval as "there is a 95% probability the true value is in here" — including 59% of...

Nadia Rahim

Pub. 26 Jul

Showing 25–33 of 33 results

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