Practical, example-driven guides to the charts behind every analysis — how to read them, when to use them, how the numbers are computed, and where people misread them. Every guide links to a free tool where you can try the concept on your own data.
A box plot (box-and-whisker plot) summarizes a distribution with five numbers: min, Q1, median, Q3, max. Learn each part, how outliers are flagged, and when to use one.
Learn to read box plots like a statistician: find the median, judge spread from the IQR, spot skewness from whisker asymmetry, and compare groups correctly.
Box plots summarize; violin plots show the full distribution shape. A side-by-side comparison of what each chart reveals, hides, and when to choose which.
IQR Tukey fences, Z-score, and median absolute deviation (MAD) compared — how each works, when each fails, and a worked numeric example.
Tukey hinges, Moore & McCabe, and linear interpolation (Hyndman & Fan types) produce different quartiles on the same data. Here's why, and which one this site uses.
Plain-language definitions of the 30 statistical terms you meet in box plots, histograms, and Q-Q plots — from mean and median to KDE, masking, and Tukey fences.
New to statistical charts? Read What is a Box Plot? first — the five-number summary underpins most of the tools on this site. Then How to Read a Box Plot turns the definitions into a repeatable reading routine.
Choosing between chart types? Box Plot vs Violin Plot covers the most common decision. Hunting anomalies? Outlier Detection Methods compares the IQR, Z-score, and MAD rules with worked numbers. Getting different quartiles from different software? Quartile Calculation Methods explains why — and which convention this site uses. For quick definitions, the Statistics Glossary covers 30 core terms in plain language.