ProbabilitySimple and Compound

Probability of Simple EventsProbability- the chance that something will

happen

Probability= Favorable/TotalSample Space – all possible outcomesFavorable – the outcome you’re interested in

Ex. The probability of flipping a coin and landing on heads.

Sample Space – Heads or TailsProb=1/2

Odds of Simple EventsOdds = favorable : unfavorable

The top of the fraction : the bottom-the topUnfavorable = total-favorable

ExThe probability of flipping a coin and landing

on heads.1:1

Probability of Simple EventsRock Paper Scissor Lizard Spock

http://www.youtube.com/watch?v=C4PWu5qZ8z8 Sample SpaceRock Paper Scissors Lizard

SpockNumber of possible outcomes = 5

Prob of Raj throwing paper = Odds=

Prob of Raj throwing lizard = Odds=

Probability of Simple EventsProb of Raj throwing paper or Spock =

Odds=

Prob of Sheldon throwing rock = Odds=

Prob of Sheldon throwing paper, scissors, lizard, or Spock= Odds=

Prob of Sheldon throwing one of the original choices = Odds=

Probability of Simple EventsSample Space for Raj and Sheldon

RR RP RS RL RSPPR PP PS PL PSPSR SP SS SL SSPLR LP LS LL LSPSPR SPP SPS SPL SPSP

Number of all possible outcomes: 25

Probability of Simple EventsProb of Raj throwing rock and Sheldon throwing

lizard= Odds=

Prob of Spock and paper being thrown=Odds=

Prob of them both throwing Spock=Odds=

 Prob of them throwing the same thing=

Odds=

Sheldon Let’s the Dice Choose Lunchhttp://www.youtube.com/watch?v=BVIjqd8DBGw

Sheldon chooses his entrée by rolling a 20 sided die. There are 5 burgers on this page and 15 other dishes. He then rolls a six sided die to choose his beverage. The beverage choices are lemonade, water, coke, mountain dew, margaritas, and strawberry daiquiris.

Prob of burger= Odds= Prob of lemonade= Odds= Prob of both= Odds=

Probability of Compound EventsCompound Events

Independent Events- Events that do not affect each other

Independent examples-Rock Paper Scissors Rolling two separate diceFlipping coins Spinning a spinner and

rolling a die

Compound Independent Probability MethodProb of Events A and B occurring = Prob of Event A*Prob of

event B

Probability of Compound EventsExamples-

What is the probability of rolling a 6 and a coin landing on heads?

Prob of rolling a six =

Prob of flipping heads =

Prob of both = Odds=

Probability of Compound EventsExamples-

What is the probability of dropping a coin down 12 stairs and it landing heads up on the 5th stair?

Prob of flipping heads =

Prob of landing of the 5th step =

Prob of both = Odds=

Probability of Compound EventsDependent Events – Events in which the outcome of

one will affect the probability of the other

Dependent examples-Picking options out of a hat Picking people out of a crowdPicking cards out of a deck

Compound Dependent Probability MethodProb of Events A and B occurring =

Prob of Event A*Modified Prob of event B

Probability of Compound EventsExamples-

There is a bag filled with 10 marbles: 6 red, 1 blue, and 3 green. What is the probability of randomly picking out a red marble then a green marble?

Prob of red =

Modified prob of green =

Prob of both = Odds=

Probability of Compound EventsExamples-

There is a bag filled with 10 marbles: 6 red, 1 blue, and 3 green. What is the probability of picking a red then a red then the blue marbles?

Prob of red = Modified prob of red = Modified prob of blue =

Prob of all = Odds=