Turning Point Dsci2710chapter5fall2011

Turning Point Dsci2710chapter5fall2011 - CHAPTER 5 :...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
1 CHAPTER 5 : Probability Concept 1 CHAPTER 4 : Probability Concept 2 CHAPTER 4 : Probability Concept 3
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Relative Frequency Approach If event A occurs m times, your estimate of the probability that A will occur in the future is P(A) = m/n Suppose that a production process has been in operation for 250 days; 220 days are accident-free. CHAPTER 4 : Probability Concept 4 Let A = a randomly chosen day in the future is free of accidents. Using the relative frequency definition, then P(A) = ???/??? = .88 (between 0 & 1) Real world terms for Probability: Percentage; Proportion; Likelihood Complement of an Event The complement of an event A is the event that A does not occur. This event is denoted by . For example:- A it i t A CHAPTER 4 : Probability Concept 5 = it rains tomorrow, = ???? A = stock market rises tomorrow, = ???? A A 1. Let A be the event that a Yellow M&M is selected from a bag with 4 Yellow, 4 Brown, and 4 Red M&Ms. What is the 33% 33% 33% probability of event A? CHAPTER 4 : Probability Concept 6 123 1. 1/2 2. 1/3 3. 1/4
Background image of page 2
3 Datacomp Survey of Microcomputer purchasers <30 30-45 >45 Age(Years) CHAPTER 4 : Probability Concept 7 30 45 Sex (U) (B) (O) Total Male(M) 60 20 40 120 Female(F) 30 10 80 100 50 200 Joint Probability There are 40 purchasers who are female and under 30 , so P ( F and U ) = 40/200 = .2 CHAPTER 4 : Probability Concept 8 What proportion are males between 30 and 45 ? This is the same as P ( M and B ) = 20/200 = .1 because 20 out of 200 satisfy both requirements. Conditional Probability Whenever you are given information and are asked to find a probability based on this information, the result is a conditional probability . This probability is written as CHAPTER 4 : Probability Concept 9 P ( A | B ) B is the event that you know occurred and A is the uncertain event whose probability you need.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Conditional Probability ( Cont .) Look for words like “of” or “given.” The vertical line indicates that the occurrence of event B is given, so the expression is read as the probability of A given B .” In the example CHAPTER 4 : Probability Concept 10 In the example, P ( M | U ) = .6 Of the purchasers who are under 30, what proportion is male? Definition Events A and B are independent if and only if: 1. P ( A | B ) = P ( A ) (assuming P ( B ) 0), or CHAPTER 4 : Probability Concept 11 2. P ( B | A ) = P ( B ) (assuming P ( A ) 0), or 3. P ( A and B ) = P ( A ) · P ( B ) Event that are not independent are dependent events.
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/13/2012 for the course DCSI 3710 taught by Professor Pavur during the Fall '11 term at North Texas.

Page1 / 17

Turning Point Dsci2710chapter5fall2011 - CHAPTER 5 :...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online