Blog · Category
Plain-language explainers of the concepts behind the numbers, so the output of every analysis makes sense.
The four capability indices in plain language — and the assumption they all share.
Oct 7, 2026 · 7 min read
On unbalanced data the same effect gets three different F-tests. Which is right?
Oct 14, 2026 · 7 min read
A p-value says whether an effect exists, not how big. Report the size too.
Oct 16, 2026 · 7 min read
PCA for categorical data: turn a big cross-tab into one readable map.
Oct 28, 2026 · 7 min read
Let 54,000 diamonds carve their own rules — and confirm the finding from a new angle.
Sep 18, 2026 · 6 min read
Name each component from its loadings — and let PCA explain a real mystery.
Sep 4, 2026 · 6 min read
When the log transform earns its place — and why it isn't just cosmetic.
Aug 28, 2026 · 6 min read
The best-cut diamonds look cheapest — until you find the confounder hiding in plain sight.
Aug 21, 2026 · 6 min read
Both compare groups, but one shows summaries and the other shows shape.
Sep 18, 2026 · 6 min read
Read every pair's relationship at once, with the significant ones highlighted.
Sep 4, 2026 · 6 min read
R², VIF, Cook's distance and residual plots — whether to believe the model.
Sep 2, 2026 · 7 min read
Loadings tell you what a component means; scores tell you where each observation sits.
Aug 21, 2026 · 7 min read
How SPC tells ordinary variation from a real change — and what the Nelson rules detect.
Aug 14, 2026 · 7 min read
What correlation does and doesn't mean, and when to use Pearson vs Spearman.
Aug 5, 2026 · 7 min read
Two measures of center that agree for symmetric data and diverge for skewed data.
Jul 29, 2026 · 6 min read
Normality, equal variance, independence — what each assumption means and how to check it.
Jul 17, 2026 · 9 min read
Median, quartiles, the IQR box, whiskers and outliers — read a box plot at a glance.
Jul 8, 2026 · 8 min read
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