Keyboard shortcuts

/ or ⌘/Ctrl K
Find a note
j / k
Next / previous section or linked note
h / l
Collapse or go to parent / expand or enter
e or Alt-click
Read a linked note here
o
Open focused note on its own
g g / G
First / last section or linked note
g h / g a
Home / all notes
g b / g t
Backlinks / table of contents
t
Cycle System, Light, Dark
? / Esc
Show / close this reference

Search: ↑/↓ or Ctrl N/P, Enter to open. Shortcuts pause while typing.

probability [bf68b582]

Tags: statistics

1. Probability Simplex [3c30ba04]

  • A shape where each vertex represents a probability
  • Example:
  Outcomes: {1, 2, 3}
  Let the probabilities be p1​,p2​,p3​.
  We know that p1​≥0, p2​≥0, p3​≥0, and p1​+p2​+p3​=1.
  Geometrically, this can be represented by a 2-simplex, which is an equilateral triangle.

  Each vertex of the triangle represents a distribution where one outcome has a probability of 1 and the others have a probability of 0.
          Vertex 1: p1​=1,p2​=0,p3​=0
          Vertex 2: p1​=0,p2​=1,p3​=0
          Vertex 3: p1​=0,p2​=0,p3​=1
      Any point inside the triangle (or on its edges) represents a probability distribution where p1​,p2​, and p3​ are non-negative and sum to 1. The closer a point is to a vertex, the higher the probability of that corresponding outcome.

2025-03-24_21-09-56_screenshot.png