Underrepresentation

Interactive comparison of two IQ-normal-distributions (Gauß curves), visualizing how over- or underrepresented a group with a shifted mean and/or spread is at a given IQ threshold, relative to a fixed reference (IQ 100, σ 15).

Preview

Live demo: https://helmutqualtinger.github.io/Underrepresentation/iq_gauss.html

What it shows

• Two true probability density curves (area = 1), plotted on a shared logarithmic y-axis:
  • Referenz — fixed at IQ 100, σ 15
  • Variable — adjustable via sliders (IQ 40–160, σ 2–30)
• A third curve, Überrepräsentierung, showing the ratio of tail areas P(Variable ≥ x) / P(Referenz ≥ x) — how many times more (or less) often the variable group appears at or above a given IQ threshold.
• Hover/touch crosshair with a tooltip reporting exact density and ratio values at any IQ.
• An expandable table of density and ratio values at every 5 IQ points across the visible range.

Usage

Open iq_gauss.html directly in a browser — it’s a single self-contained file (no build step, no dependencies). Drag the IQ and Streuung (σ) sliders under “Variable Verteilung” to compare distributions.

Tech

Plain HTML/CSS/SVG + vanilla JavaScript. No frameworks, no external assets. Supports light/dark theme via prefers-color-scheme and data-theme.