This n-demo stays in the repository. It is not Week 9. Week 9 is game.html. A mean from twenty of your own trials is still a sketch. Rewrite a Week 2 or Week 5 sentence so it states n, spread, and what you will not claim.
Draws from a made-up reaction-time distribution (mean 320 ms, SD 40 ms). Move n and redraw. The true mean does not change. Your sample mean does.