Expression of Simple Probability
Formula: number of "favorable"
outcomes
divided by
number of possible outcomes
e.g. Survival Odds In Russian
Roulette
(5 empty chambers and 1 bullet)
5 favorable / 6 possible outcomes
= 5/6 or 83.33% survival probability
Compound Probability
Independent Events

surviving multiple rounds of Russian
Roulette with spin of chamber between pulls: 5/6 x 5/6, etc.

repeatedly drawing ace from deck
of cards with replacement after each draw: 4/52 x 4/52, etc.
Dependent Events

surviving multiple rounds of Russian
Roulette without spin of chamber between pulls: 5/6 x 4/5 x 3/4
x 2/3 x 1/2; then BANG

repeatedly drawing ace from deck
of cards without replacement after each draw: 4/52 x 3/51 x 2/50,
1/49; then ø
Types of Probability
Classical

Odds Based On Established Set Of
Relations
Relative Frequency

Odds Based On Statistics About Past
Occurrences
Subjective

Odds Based On Neither Established
Set Nor Past Occurrences
Probability of Nuclear War
>0%

action

relevant

<100%
