Six ChapterDay Three

Probability Rules

P. 423 37-41 and 44 P. 430 45,48,51 P. 432 54,57,60

Homework

Addition Rule for Disjoint Events P(A or B) = P(A) + P(B)

Calculate the probability of picking a king or a queen from a standard deck of cards.

P(King or Queen) = p(king) + p(queen)

Example

P(Ac) = 1 – p(A)

Find the probability of not choosing a king from a standard deck of cards.

The Complement Rule

P(A or B) = p(A) + P(B) – p(A and B)

The Addition Rule for non disjoint Events

At a certain school there are 100 students. 36 students take Calculus 50 students take AP Statistics and 25 take both.

Make a Venn Diagram and calculate the probability that a student takes either AP Calculus or AP Statistics

Example

Example Give the sample space for rolling two dice.

Then calculate the following:

P(sum is five)

P( sum is a prime number)

P( sum is not a perfect square)

Roll a regular tetrahedral die.

Construct a probability Model for rolling such a die.

Construct a probability model for the sum when two such die are rolled.

Example

Independent Events Tell if each of the following represent

independent events.

Rolling a die twice A = getting a six on the fist roll B = getting a six on second roll.

Picking two cards from a deck without replacement. A = Getting a black card on first draw B = Getting a black card on second draw

Roll a die twice. Calculate probability that you get six on both rolls.

P(A and B) =

Draw two cards from a deck without replacement. Calculate the probability of getting to black cards. (Note: Draws are not independent)

Independent Events