Conditional Probability If two events are not mutually exclusive, the fact that we know that B has happened will have an effect on the probability of A.

Slides:



Advertisements
Similar presentations
E(X 2 ) = Var (X) = E(X 2 ) – [E(X)] 2 E(X) = The Mean and Variance of a Continuous Random Variable In order to calculate the mean or expected value of.
Advertisements

Disjointed and Overlapping Event Disjointed events (mutually exclusive) - are events that have no outcome in common Overlapping events- events that have.
Probability Theory and Statistics
Thinking Mathematically
Review Probabilities –Definitions of experiment, event, simple event, sample space, probabilities, intersection, union compliment –Finding Probabilities.
The Laws of Probability
Dependent and Independent Events. If you have events that occur together or in a row, they are considered to be compound events (involve two or more separate.
Independent Events Let A and B be two events. It is quite possible that the percentage of B embodied by A is the same as the percentage of S embodied by.
© 2013 Pearson Education, Inc. Active Learning Lecture Slides For use with Classroom Response Systems Introductory Statistics: Exploring the World through.
5.2A Probability Rules! AP Statistics.
5.3B Conditional Probability and Independence Multiplication Rule for Independent Events AP Statistics.
Conditional Probability
8-5: Adding Probabilities English Casbarro Unit 8.
A.P. STATISTICS LESSON 6.3 ( DAY 2 ) GENERAL PROBABILITY RULES ( EXTENDED MULTIPLICATION RULES )
AP Statistics Chapter 6 Notes. Probability Terms Random: Individual outcomes are uncertain, but there is a predictable distribution of outcomes in the.
COUNTING RULES PROBLEMS 1. How many different ways can a nurse visit 9 patients if she wants to visit them all in one day? If she wants to visit only 5?
Random Experiment Random Variable: Continuous, Discrete Sample Space: S Event: A, B, E Null Event Complement of an Event A’ Union of Events (either, or)
Notes Over 12.2 Finding Combinations 1. An ice cream shop has a choice of 10 toppings. In how many ways can you choose 3 different toppings for your ice.
Tree Diagram Worksheet
Chapter 12 Probability. Chapter 12 The probability of an occurrence is written as P(A) and is equal to.
AP Review Day 2: Discrete Probability. Basic Probability Sample space = all possible outcomes P(A c ) = 1 – P(A) Probabilities have to be between 0 and.
Probability(C14-C17 BVD) C15: Probability Rules. * OR – In probability language, OR means that either event happening or both events happening in a single.
Dr. Omar Al Jadaan Probability. Simple Probability Possibilities and Outcomes Expressed in the form of a fraction A/B Where A is the occurrence B is possible.
Bayes’ Theorem Bayes’ Theorem allows us to calculate the conditional probability one way (e.g., P(B|A) when we know the conditional probability the other.
AP STATISTICS LESSON 6.3 (DAY 1) GENERAL PROBABILITY RULES.
Recap from last lesson Compliment Addition rule for probabilities
Probability You’ll probably like it!. Probability Definitions Probability assignment Complement, union, intersection of events Conditional probability.
12/7/20151 Math b Conditional Probability, Independency, Bayes Theorem.
Chapter 4 (continued) Nutan S. Mishra Department of Mathematics and Statistics University of South Alabama.
2. Introduction to Probability. What is a Probability?
Probability Rules. We start with four basic rules of probability. They are simple, but you must know them. Rule 1: All probabilities are numbers between.
Probability. Rules  0 ≤ P(A) ≤ 1 for any event A.  P(S) = 1  Complement: P(A c ) = 1 – P(A)  Addition: If A and B are disjoint events, P(A or B) =
Conditional Probability: the likelihood that an event will occur GIVEN that another event has already occurred. A two way table & tree diagrams can represent.
Conditional Probability and Independence. Learning Targets 1. I can use the multiplication rule for independent events to compute probabilities. 2. I.
In-Class Exercises: Axioms of Probability
Let A and B be two independent events for which P(A) = 0.15 and P(B) = 0.3. Find P(A and B).
9-7Independent and Dependent Events 9-7 Independent and Dependent Events (pg ) Indicator: D7.
Independent Events The occurrence (or non- occurrence) of one event does not change the probability that the other event will occur.
Starter P(A) = ½, P(B) = ⅓ and P(A B) = p Find p if:
I can find probabilities of compound events.. Compound Events  Involves two or more things happening at once.  Uses the words “and” & “or”
Probability Any event occurring as a result of a random experiment will usually be denoted by a capital letter from the early part of the alphabet. e.g.
P(B) = Triangle Area P(A) = Oval Area P(A or B) = r + w + g P(A and B) = w So, P(A) + P(B) = r + w + g + w The Addition Rule for 2 events A and B P(A or.
STATISTICS 6.0 Conditional Probabilities “Conditional Probabilities”
© 2013 Pearson Education, Inc. Reading Quiz For use with Classroom Response Systems Introductory Statistics: Exploring the World through Data, 1e by Gould.
S ECTION 7.2: P ROBABILITY M ODELS. P ROBABILITY M ODELS A Probability Model describes all the possible outcomes and says how to assign probabilities.
Review Conditional Probability –Denoted P(A|B), it represents the probability that A will occur given that B occurred. Independent events –Two events A.
Copyright © 2011 by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Chapter 4 Probability.
Chapter 15: Probability Rules! Ryan Vu and Erick Li Period 2.
Adding Probabilities 12-5
Probability Using Venn Diagrams
Chapter 4 Probability.
Probabilities.
Statistics 300: Introduction to Probability and Statistics
12.4 Probability of Compound Events
Multiplication Rule and Conditional Probability
Lecture 3 Probability By Aziza Munir.
STAT 203 Tree Diagrams and Bayes’ Rule
Conditional Probability AGENDA
I can find probabilities of compound events.
Mutually exclusive nothing in common.
Introduction to Probability & Statistics Expectations
Mutually Exclusive Events
LESSON 5: PROBABILITY Outline Probability Events
General Probability Rules
the addition law for events that are not mutually exclusive
Probability Multiplication law for dependent events
Note 9: Laws of Probability
Review: Mini-Quiz Combined Events
Chapter 5 – Probability Rules
Probability.
Presentation transcript:

Conditional Probability If two events are not mutually exclusive, the fact that we know that B has happened will have an effect on the probability of A. P(A|B) = P(A B) P(B) P(A|B) is the probability of A given that B has occurred. This formula can be changed to P(B|A) = P(A B) P(A) In order to calculate the probability of B given that A has occurred.

Example A sub-committee of 5 is chosen from a committee of 10 men and 8 women. Find the probability of choosing exactly 2 women given that the sub-committee contains at least 1 woman. A - exactly 2 women B – at least 1 woman Possible combinations = 18 C 5 = C 2 x 10 C 3 = 28 x 120 = 3360 P(A B) = 3360 = P(A B) = 2 women and at least 1 woman. = 2 women. P(A|B) = P(A B) P(B)

10 C 5 = 252 P(B) = = P(A|B) = P(A B) = 20/51 = 40 P(B) 33/34 99 Exercise 3.5 Mathematics Statistics Unit S1 - WJEC Homework 4 P(B) = at least 1 woman = 1 – no women