Quiz 3
Registry Synced

Chatty reference · stats1 week 5

48 words
1 min read
2026-08-16

25. Stats W5 — Counting

Concepts:
  • Addition rule
  • Multiplication rule
  • Factorials
Factorial:
n!=n(n−1)(n−2)⋯1n!=n(n-1)(n-2)\cdots1

Addition rule

Use when alternatives are mutually exclusive:
N=N1+N2+⋯N=N_1+N_2+\cdots

Multiplication rule

Use for sequential choices:
N=N1N2⋯N=N_1N_2\cdots
The real skill is recognizing whether a problem is additive or multiplicative.
Document outline

Keep your place and jump directly to a heading.

Table of contents

No note selected

Open a chapter to see its outline, backlinks, and sources here.

Open libraryCheckpoint desk