Pre Algebra Periods 1, 2, & 4

Probability and Odds 6-4

Outcomes-- possible results of any action

an event-- any outcome or group of outcomes.

Probability of an even is expressed either as a ratio or as a percent (%)

P(event) = # of favorable outcomes/ # of possible outcomes
The Probability of finding an 's' in Mississippi
P(s) = 4/11 = .363636... = 36 4/11%

Odds

favorable outcomes/ unfavorable outcomes

DO NOT WRITE AS A PERCENT

odd of getting a 's' in Mississippi becomes 4/7 or 4:7 or 4 to 7


The odds of UCLA winning the NCAA 3:1 3 favorable/1 unfavorable

changing that to probability it becomes 3/4 or 75%


probability -- the denominator is TOTAL outcomes

odds-- the denominator is unfavorable outcomes.