Drag rhythmic values into up to 8 beat blocks per line to build a drum groove, or click a tile then click a block to place it — handy on a trackpad.

🎵 Probability Lesson 5: Expected Value of a Discrete Random Variable — Compute E[X] = Σ x·P(x) mess around all you want, nothing here saves
134 BPM
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Probability, Lesson 5: Expected Value of a Discrete Random Variable

Math skill: Compute E[X] = Σ x·P(x)

How the beat teaches it: Every slot gives a random variable X's possible values and their probabilities — multiply each value by its probability and add the results. Build that many notes anywhere in the kit.

This is lesson 5 of 24 in RockBlocks Math, Probability, a free course where every lesson turns a math idea into something you can count, hear, and play. The previous lesson, Finding False Positives,” covered find False Positives = Total Positives - True Positives. Next is Lesson 6, Variance of a Two-Outcome Random Variable.”

Every slot above (A, B, C, D) is its own question, and it’s a real, blank RockBlocks beat the whole time — the same drag-and-drop tiles, kit, tempo, sheet music, and drummer view as anywhere else on the site. Tap ❓ Questionin the corner to read the current slot’s problem, build your answer right in the grid, then tap ✓ Check Answerto grade it. Once you’re done, keep going: expand the beat, drop it into a Stack, or save a copy to your own page — nothing here overwrites the lesson itself, so every visitor still starts from the same blank slots.