this is my notes from MITx: 6.431x Probability - The Science of Uncertainty and Data

## Lec. 1: Probability models and axioms

### samples space

- two steps

describe possible outcome

sets of possibile outcome

describe beliefs about likelihood of outcomes

## probility axioms

- Event:a subset of sample space

probility is assigned to events

- Axioms

- nonegative: P(A) > 0
- normalization: $P(\Omega)>0$
- additivity:if $P(A) \cap P(B)= \varnothing ;then P(A \cup B)=P(A)+P(B)$