12.1/12.2 Probability

Quick Vocab: Random experiment: “random” act, no way of knowing ahead of time Outcome: results of a random experiment Event: a set of outcomes Sample space: the set ALL possible outcomes

Probability P(Event) = P(E) Toss of coin: Probability of landing on heads: P(H) = “Probability of an event”

Probability P(will definitely occur) = 1 ex: Have 1 die P(never occur) = 0 ex: Have 1 die = 1 P(roll a #) P(roll a letter)= 0

Probability Two dice are rolled and the numbers are noted. Find the probability of each event. a) The sum of the numbers is less than 5

Possibilities when 2 dice are rolled (Pg. 632 in book) Sum < 5 ? TOTAL = 36

Probability Two dice are rolled and the numbers are noted. Find the probability of each event. a) The sum of the numbers is less than 5 b) The sum of the numbers is 4 or 5.

Possibilities when 2 dice are rolled Sum = 4 or 5 ?

Probability Two dice are rolled and the numbers are noted. Find the probability of each event. a) The sum of the numbers is less than 5 b) The sum of the numbers is 4 or 5. P(4 or 5) =

Standard Deck of Cards 52 cards in the deck 26 black, 26 red 4 suits: hearts, diamonds, clubs, spades 13 of each suit Face cards: Have a FACE!! (not Ace) Clubs (Black) Hearts (Red) Diamonds (Red) Spades (Black)

A card is drawn from a standard deck of 52 cards. What is the probability that the following occurs? P( a red card) # of red cards in deck? P(a spade) # of  s in deck? 

A card is drawn from a standard deck of 52 cards. What is the probability that the following occurs? TOO: P(the card is a heart) # of s in deck? P(the card is a 3 or 4) # of 3s? # of 4s?

A card is drawn from a standard deck of 52 cards. What is the probability that the following occurs? TOO: P(between a 2 and 5, inclusive) # of each ? 4 2, 3, 4, and 5: 4 x 4=16

A nickel, dime and quarter are flipped. H=heads, T=tails How many elements are in the sample space? Find P(exactly 2 tails) P(nickel or dime are heads) 8  HHH, HHT, HTH, THH, TTH, THT, HTT, TTT 

A nickel, dime and quarter are flipped. H=heads, T=tails TOO: Find P(at least 2 tails) P(4 heads)  HHH, HHT, HTH, THH, TTH, THT, HTT, TTT 

Homework Pg. 633 #1-13, Pg Q1-10, 1 & 2