Samples are drawn at random by your browser, so every run is a little different. Changing a setting starts a fresh batch so the capture rate always matches one method.
Sketch first, then compute. The worked solution builds line by line after a correct answer or when you ask for it.
Your jobEach round changes one thing (or two) about how an interval is built. Decide whether the new interval is wider, narrower or the same width, as fast as you can. Keys 1 2 3 pick an answer.
Press Start to begin.
Fictional settings and practice numbers chosen to look realistic. They are not clinical reference values or advice.
Wrong picks are fine here. Each one tells you why.