Five short steps. By the end you'll know what the number means.
Here are 14 students. How long each one revised is the left-to-right position. The mark they got is the height. Tap any dot.
These are the same 44 points every time — only rearranged. Drag the slider and watch what each value of r actually looks like.
Both clouds follow the same line. The only thing that changed is how closely the dots hug it — and that is exactly what r measures.
Same line, different spread — so a steeper line does not mean a stronger correlation.
All three of these score about r = +0.8 — the same as a solid straight-line relationship. None of them is a straight line.
One real round. Drag to your best guess, then check. The true value gets marked on the slider so you can see the gap.
Part of the LLL Series OSS.