4.8 Chapter 4 Formulas

Complement Rules: P(A) + P(A^C) = 1 P(A) = 1 – P(A^C) P(A^C) = 1 – P(A)	Mutually Exclusive Events: P(A ∩ B) = 0
Union Rule: P(A U B) = P(A) + P(B) – P(A ∩ B)	Independent Events: P(A ∩ B) = P(A) ‧ P(B)
Intersection Rule: P(A ∩ B) = P(A) ‧ P(B\|A)	Conditional Probability Rule: $P(A \mid B)=\frac{P(A \cap B)}{P(B)}$
Fundamental Counting Rule: m₁·m₂···m_n	Factorial Rule: n! = n·(n – 1)·(n – 2)···3·2·1
Combination Rule: ${ }_{\mathrm{n}} \mathrm{C}_{\mathrm{r}}=\frac{n !}{(r !(n-r) !)}$	Permutation Rule: ${ }_{\mathrm{n}} \mathrm{P}_{\mathrm{r}}=\frac{n !}{(n-r) !}$

Adapted from Mostly Harmless Statistics by Rachel Webb (Portland State University, https://mostlyharmlessstat.wixsite.com/webpage), © Rachel Webb, licensed under CC BY-SA 4.0. Changes were made. License: CC-BY-SA-4.0.