Will Landau. Feb 21, 2013

Size: px
Start display at page:

Download "Will Landau. Feb 21, 2013"

Transcription

1 Iowa State University Feb 21, 2013 Iowa State University Feb 21, / 31

2 Outline Iowa State University Feb 21, / 31

3 random variables Two types of random variables: Discrete random variable: one that can only take on a set of isolated points (X, N, and S). random variable: one that can fall in an interval of real numbers (T and Z). Examples of continuous random variables: Z the amount of torque required to loosen the next bolt (not rounded). T the time you ll have to wait for the next bus home. C outdoor temperature at 3:17 PM tomorrow. L length of the next manufactured part. Iowa State University Feb 21, / 31

4 random variables V : % yield of the next run of a chemical process. Y : % yield of a better process. How do we mathematically distinguish between V and Y, given: Each has the same range: 0% V, Y 100% There are uncountably many possible values in this range. We want to show that Y tends to take on higher % yield values than V. Iowa State University Feb 21, / 31

5 V and Y have continuous probability s of V of Y f(v) f(y) v y The heights of these curves are not themselves probabilities. However, the the curves tell us that process Y will yield more product per run on average than process X. Iowa State University Feb 21, / 31

6 A generic probability density function (pdf) Iowa State University Feb 21, / 31

7 Outline Iowa State University Feb 21, / 31

8 Definition: probability density function (pdf) A probability density function (pdf) of a continuous random variable X is a function f (x) with: f (x) 0 for all x. f (x)dx 1 P(a X b) b a f (x)dx, a b The pdf is the continuous analogue of a discrete random variable s probability mass function. Iowa State University Feb 21, / 31

9 Example Let Y be the time delay (s) between a 60 Hz AC circuit and the movement of a motor on a different circuit. Say Y has a density of the form: { c 0 < y < 1 f (y) 60 0 otherwise we say that Y has a Uniform(0, 1/60). f (y) must integrate to 1: 1 f (y)dy 0 0dy + 1/60 0 cdy + 0dy c 1/60 60 hence, c 60, and: f (y) { 60 0 < y < otherwise Iowa State University Feb 21, / 31

10 A look at the density Iowa State University Feb 21, / 31

11 Your turn: calculate the following probabilities. f (y) 1. P(Y ) 2. P(Y > 1 70 ) 3. P( Y < ) 4. P( Y 1 > P(Y 1 80 ) 110 ) { 60 0 y otherwise Iowa State University Feb 21, / 31

12 Answers: calculate the following probabilities 1. P(Y ) P( < Y ) 1/100 0 f (y)dy 0dy / dy Iowa State University Feb 21, / 31

13 2. P(Y > 1 70 ) P( 1 70 < Y ) 1/70 1/60 1/70 f (y)dy 60dy + 0dy 1/60 60y 1/60 1/70 ( ) Iowa State University Feb 21, / 31

14 3. P( Y < ) P( < Y < ) 1/120 1/ /120 f (y)dy 0dy + 1/ y 1/120 0 ( ) dy Iowa State University Feb 21, / 31

15 4. P( Y > ) P(Y > or Y < ) P(Y > or Y < ) P(Y > ) + P(Y < ) 31/2200 1/60 31/2200 f (y)dy + 60dy + 9/2200 1/60 0dy + f (y)dy 9/ /60 31/2200 ( ) dy Iowa State University Feb 21, / 31

16 5. P(Y 1 80 ) P( 1 80 Y 1 80 ) 1/80 1/80 f (y)dy 1/80 1/80 ( 60 1/80 1 1/ ) dy In fact, for any random variable X and any real number a: P(X a) P(a X a) a a f (x)dx 0 Iowa State University Feb 21, / 31

17 Outline Iowa State University Feb 21, / 31

18 functions (cdf) The cumulative function of a random variable X is a function F such that: In other words: F (x) P(X x) d F (x) f (x) dx x f (t)dt As with discrete random variables, F has the following properties: F (x) 0 for all x. F is monotonically increasing. lim x F (x) 0 lim x F (x) 1 Iowa State University Feb 21, / 31

19 Example: calculating the cdf of Y Remember: For y 0: For 0 < y < 1/60: f Y (y) { 60 0 < y < 1/60 0 otherwise y 0 F (y) P(Y y) f (t)dt 0dt 0 y 0 y F (y) P(Y y) f (t)dt 0dt + 60dt 60y 0 For y 1/60: y F (y) P(Y y) 0 0dt + f (t)dt 1/ dt + 0dt 1 1/60 Iowa State University Feb 21, / 31

20 A look at the cdf Iowa State University Feb 21, / 31

21 Your turn: calculate the following using the cdf 1. F (1/70) 2. P(Y 1 80 ) 3. P(Y > ) 4. P( Y ) 0 y 0 F (y) 60y 0 < y 1 1 y > Iowa State University Feb 21, / 31

22 Answers: calculate the following using the cdf 1. F ( 1 70 ) P(Y 1 80 ) F ( 1 80 ) P(Y > ) 1/150 f (y)dy f (y)dy 1/150 1 F (1/150) f (y)dy 3 5 In fact, for any random variable X, discrete or continuous: P(X x) 1 P(X < x) Iowa State University Feb 21, / 31

23 4. P( Y ) 1/120 1/130 1/120 f (y)dy f (y)dy 1/130 F (1/120) F (1/130) 60(1/120) 60(1/130) 1/ f (y)dy Iowa State University Feb 21, / 31

24 Outline Iowa State University Feb 21, / 31

25 The A random variable X has an Exponential(α) if: { 1 f (x) α e x/α x > 0 0 otherwise Iowa State University Feb 21, / 31

26 Your turn: for X Exp(2), calculate the following f (x) 1. P(X 1) 2. P(X > 5) 3. The cdf F of X { 1 2 e x/2 x > 0 0 otherwise Iowa State University Feb 21, / 31

27 Answers: for X Exp(2), calculate the following 1. P(X 1) 1 0 f (x)dx 1 1 0dx e x/2 dx 0 + ( e x/2 1 0 e 1/2 ( e 0/2 ) 1 e 1/ Iowa State University Feb 21, / 31

28 2. P(X > 5) 5 5 f (x)dx e x/ e x/2 dx e /2 + e 5/2 e 5/ Iowa State University Feb 21, / 31

29 3. For x < 0: For x 0: F (x) P(X x) x 0dx 0 F (x) P(X x) 0 0dx + x x x 0 f (x)dx) f (x)dx 1 2 e t/2 dt e t/2 x 0 e x/2 ( e 0/2 ) 1 e x/2 Iowa State University Feb 21, / 31

30 Hence: F (x) { 1 e x/2 x 0 0 otherwise In general, an Exp(α) random variable has cdf: { 1 e x/α x 0 F (x) 0 otherwise Iowa State University Feb 21, / 31

31 Uses of the Exp(α) random variable An Exp(α) random variable measures the waiting time until a specific event that has an equal chance of happening at any point in time. Examples: Time between your arrival at a bus stop and the moment the bus comes. Time until the next person walks inside the library. Time until the next car accident on a stretch of highway. Iowa State University Feb 21, / 31

p. 6-1 Continuous Random Variables p. 6-2

p. 6-1 Continuous Random Variables p. 6-2 Continuous Random Variables Recall: For discrete random variables, only a finite or countably infinite number of possible values with positive probability (>). Often, there is interest in random variables

More information

SDS 321: Introduction to Probability and Statistics

SDS 321: Introduction to Probability and Statistics SDS 321: Introduction to Probability and Statistics Lecture 14: Continuous random variables Purnamrita Sarkar Department of Statistics and Data Science The University of Texas at Austin www.cs.cmu.edu/

More information

Continuous distributions

Continuous distributions CHAPTER 7 Continuous distributions 7.. Introduction A r.v. X is said to have a continuous distribution if there exists a nonnegative function f such that P(a X b) = ˆ b a f(x)dx for every a and b. distribution.)

More information

5.2 Continuous random variables

5.2 Continuous random variables 5.2 Continuous random variables It is often convenient to think of a random variable as having a whole (continuous) interval for its set of possible values. The devices used to describe continuous probability

More information

Continuous Random Variables

Continuous Random Variables 1 Continuous Random Variables Example 1 Roll a fair die. Denote by X the random variable taking the value shown by the die, X {1, 2, 3, 4, 5, 6}. Obviously the probability mass function is given by (since

More information

Continuous Random Variables

Continuous Random Variables Contents IV Continuous Random Variables 1 13 Introduction 1 13.1 Probability Mass Function Does Not Exist........................... 1 13.2 Probability Distribution.....................................

More information

Basics of Stochastic Modeling: Part II

Basics of Stochastic Modeling: Part II Basics of Stochastic Modeling: Part II Continuous Random Variables 1 Sandip Chakraborty Department of Computer Science and Engineering, INDIAN INSTITUTE OF TECHNOLOGY KHARAGPUR August 10, 2016 1 Reference

More information

Continuous Random Variables

Continuous Random Variables Continuous Random Variables Recall: For discrete random variables, only a finite or countably infinite number of possible values with positive probability. Often, there is interest in random variables

More information

General Random Variables

General Random Variables 1/65 Chia-Ping Chen Professor Department of Computer Science and Engineering National Sun Yat-sen University Probability A general random variable is discrete, continuous, or mixed. A discrete random variable

More information

Continuous random variables

Continuous random variables Continuous random variables Continuous r.v. s take an uncountably infinite number of possible values. Examples: Heights of people Weights of apples Diameters of bolts Life lengths of light-bulbs We cannot

More information

Brief Review of Probability

Brief Review of Probability Maura Department of Economics and Finance Università Tor Vergata Outline 1 Distribution Functions Quantiles and Modes of a Distribution 2 Example 3 Example 4 Distributions Outline Distribution Functions

More information

Math438 Actuarial Probability

Math438 Actuarial Probability Math438 Actuarial Probability Jinguo Lian Department of Math and Stats Jan. 22, 2016 Continuous Random Variables-Part I: Definition A random variable X is continuous if its set of possible values is an

More information

Lecture 3: Random variables, distributions, and transformations

Lecture 3: Random variables, distributions, and transformations Lecture 3: Random variables, distributions, and transformations Definition 1.4.1. A random variable X is a function from S into a subset of R such that for any Borel set B R {X B} = {ω S : X(ω) B} is an

More information

Exponential Distribution and Poisson Process

Exponential Distribution and Poisson Process Exponential Distribution and Poisson Process Stochastic Processes - Lecture Notes Fatih Cavdur to accompany Introduction to Probability Models by Sheldon M. Ross Fall 215 Outline Introduction Exponential

More information

SDS 321: Introduction to Probability and Statistics

SDS 321: Introduction to Probability and Statistics SDS 321: Introduction to Probability and Statistics Lecture 17: Continuous random variables: conditional PDF Purnamrita Sarkar Department of Statistics and Data Science The University of Texas at Austin

More information

HW7 Solutions. f(x) = 0 otherwise. 0 otherwise. The density function looks like this: = 20 if x [10, 90) if x [90, 100]

HW7 Solutions. f(x) = 0 otherwise. 0 otherwise. The density function looks like this: = 20 if x [10, 90) if x [90, 100] HW7 Solutions. 5 pts.) James Bond James Bond, my favorite hero, has again jumped off a plane. The plane is traveling from from base A to base B, distance km apart. Now suppose the plane takes off from

More information

Lecture 4. Continuous Random Variables and Transformations of Random Variables

Lecture 4. Continuous Random Variables and Transformations of Random Variables Math 408 - Mathematical Statistics Lecture 4. Continuous Random Variables and Transformations of Random Variables January 25, 2013 Konstantin Zuev (USC) Math 408, Lecture 4 January 25, 2013 1 / 13 Agenda

More information

Continuous random variables

Continuous random variables Continuous random variables CE 311S What was the difference between discrete and continuous random variables? The possible outcomes of a discrete random variable (finite or infinite) can be listed out;

More information

STAT 509 Section 3.4: Continuous Distributions. Probability distributions are used a bit differently for continuous r.v. s than for discrete r.v. s.

STAT 509 Section 3.4: Continuous Distributions. Probability distributions are used a bit differently for continuous r.v. s than for discrete r.v. s. STAT 509 Section 3.4: Continuous Distributions Probability distributions are used a bit differently for continuous r.v. s than for discrete r.v. s. A continuous random variable is one for which the outcome

More information

Chapter 4: Continuous Probability Distributions

Chapter 4: Continuous Probability Distributions Chapter 4: Continuous Probability Distributions Seungchul Baek Department of Statistics, University of South Carolina STAT 509: Statistics for Engineers 1 / 57 Continuous Random Variable A continuous random

More information

4 Pairs of Random Variables

4 Pairs of Random Variables B.Sc./Cert./M.Sc. Qualif. - Statistical Theory 4 Pairs of Random Variables 4.1 Introduction In this section, we consider a pair of r.v. s X, Y on (Ω, F, P), i.e. X, Y : Ω R. More precisely, we define a

More information

CS145: Probability & Computing

CS145: Probability & Computing CS45: Probability & Computing Lecture 0: Continuous Bayes Rule, Joint and Marginal Probability Densities Instructor: Eli Upfal Brown University Computer Science Figure credits: Bertsekas & Tsitsiklis,

More information

STAT Chapter 5 Continuous Distributions

STAT Chapter 5 Continuous Distributions STAT 270 - Chapter 5 Continuous Distributions June 27, 2012 Shirin Golchi () STAT270 June 27, 2012 1 / 59 Continuous rv s Definition: X is a continuous rv if it takes values in an interval, i.e., range

More information

Chapter 3 sections. SKIP: 3.10 Markov Chains. SKIP: pages Chapter 3 - continued

Chapter 3 sections. SKIP: 3.10 Markov Chains. SKIP: pages Chapter 3 - continued Chapter 3 sections Chapter 3 - continued 3.1 Random Variables and Discrete Distributions 3.2 Continuous Distributions 3.3 The Cumulative Distribution Function 3.4 Bivariate Distributions 3.5 Marginal Distributions

More information

STAT509: Continuous Random Variable

STAT509: Continuous Random Variable University of South Carolina September 23, 2014 Continuous Random Variable A continuous random variable is a random variable with an interval (either finite or infinite) of real numbers for its range.

More information

Solution to Assignment 3

Solution to Assignment 3 The Chinese University of Hong Kong ENGG3D: Probability and Statistics for Engineers 5-6 Term Solution to Assignment 3 Hongyang Li, Francis Due: 3:pm, March Release Date: March 8, 6 Dear students, The

More information

Lecture 11. Probability Theory: an Overveiw

Lecture 11. Probability Theory: an Overveiw Math 408 - Mathematical Statistics Lecture 11. Probability Theory: an Overveiw February 11, 2013 Konstantin Zuev (USC) Math 408, Lecture 11 February 11, 2013 1 / 24 The starting point in developing the

More information

S n = x + X 1 + X X n.

S n = x + X 1 + X X n. 0 Lecture 0 0. Gambler Ruin Problem Let X be a payoff if a coin toss game such that P(X = ) = P(X = ) = /2. Suppose you start with x dollars and play the game n times. Let X,X 2,...,X n be payoffs in each

More information

STAT 516: Basic Probability and its Applications

STAT 516: Basic Probability and its Applications Lecture 4: Random variables Prof. Michael September 15, 2015 What is a random variable? Often, it is hard and/or impossible to enumerate the entire sample space For a coin flip experiment, the sample space

More information

The Normal Distribuions

The Normal Distribuions The Normal Distribuions Sections 5.4 & 5.5 Cathy Poliak, Ph.D. cathy@math.uh.edu Office in Fleming 11c Department of Mathematics University of Houston Lecture 15-3339 Cathy Poliak, Ph.D. cathy@math.uh.edu

More information

Chapter 3 sections. SKIP: 3.10 Markov Chains. SKIP: pages Chapter 3 - continued

Chapter 3 sections. SKIP: 3.10 Markov Chains. SKIP: pages Chapter 3 - continued Chapter 3 sections 3.1 Random Variables and Discrete Distributions 3.2 Continuous Distributions 3.3 The Cumulative Distribution Function 3.4 Bivariate Distributions 3.5 Marginal Distributions 3.6 Conditional

More information

Mathematical Statistics 1 Math A 6330

Mathematical Statistics 1 Math A 6330 Mathematical Statistics 1 Math A 6330 Chapter 2 Transformations and Expectations Mohamed I. Riffi Department of Mathematics Islamic University of Gaza September 14, 2015 Outline 1 Distributions of Functions

More information

GOV 2001/ 1002/ Stat E-200 Section 1 Probability Review

GOV 2001/ 1002/ Stat E-200 Section 1 Probability Review GOV 2001/ 1002/ Stat E-200 Section 1 Probability Review Solé Prillaman Harvard University January 28, 2015 1 / 54 LOGISTICS Course Website: j.mp/g2001 lecture notes, videos, announcements Canvas: problem

More information

Moments. Raw moment: February 25, 2014 Normalized / Standardized moment:

Moments. Raw moment: February 25, 2014 Normalized / Standardized moment: Moments Lecture 10: Central Limit Theorem and CDFs Sta230 / Mth 230 Colin Rundel Raw moment: Central moment: µ n = EX n ) µ n = E[X µ) 2 ] February 25, 2014 Normalized / Standardized moment: µ n σ n Sta230

More information

Functions of Several Random Variables (Ch. 5.5)

Functions of Several Random Variables (Ch. 5.5) (Ch. 5.5) Iowa State University Mar 7, 2013 Iowa State University Mar 7, 2013 1 / 37 Outline Iowa State University Mar 7, 2013 2 / 37 several random variables We often consider functions of random variables

More information

Gamma and Normal Distribuions

Gamma and Normal Distribuions Gamma and Normal Distribuions Sections 5.4 & 5.5 Cathy Poliak, Ph.D. cathy@math.uh.edu Office in Fleming 11c Department of Mathematics University of Houston Lecture 15-3339 Cathy Poliak, Ph.D. cathy@math.uh.edu

More information

3 Continuous Random Variables

3 Continuous Random Variables Jinguo Lian Math437 Notes January 15, 016 3 Continuous Random Variables Remember that discrete random variables can take only a countable number of possible values. On the other hand, a continuous random

More information

18.440: Lecture 19 Normal random variables

18.440: Lecture 19 Normal random variables 18.440 Lecture 19 18.440: Lecture 19 Normal random variables Scott Sheffield MIT Outline Tossing coins Normal random variables Special case of central limit theorem Outline Tossing coins Normal random

More information

Probability (continued)

Probability (continued) DS-GA 1002 Lecture notes 2 September 21, 15 Probability (continued) 1 Random variables (continued) 1.1 Conditioning on an event Given a random variable X with a certain distribution, imagine that it is

More information

1 Solution to Problem 2.1

1 Solution to Problem 2.1 Solution to Problem 2. I incorrectly worked this exercise instead of 2.2, so I decided to include the solution anyway. a) We have X Y /3, which is a - function. It maps the interval, ) where X lives) onto

More information

Math Spring Practice for the Second Exam.

Math Spring Practice for the Second Exam. Math 4 - Spring 27 - Practice for the Second Exam.. Let X be a random variable and let F X be the distribution function of X: t < t 2 t < 4 F X (t) : + t t < 2 2 2 2 t < 4 t. Find P(X ), P(X ), P(X 2),

More information

Chapter 4: Continuous Random Variable

Chapter 4: Continuous Random Variable Chapter 4: Continuous Random Variable Shiwen Shen University of South Carolina 2017 Summer 1 / 57 Continuous Random Variable A continuous random variable is a random variable with an interval (either finite

More information

Why study probability? Set theory. ECE 6010 Lecture 1 Introduction; Review of Random Variables

Why study probability? Set theory. ECE 6010 Lecture 1 Introduction; Review of Random Variables ECE 6010 Lecture 1 Introduction; Review of Random Variables Readings from G&S: Chapter 1. Section 2.1, Section 2.3, Section 2.4, Section 3.1, Section 3.2, Section 3.5, Section 4.1, Section 4.2, Section

More information

2 Functions of random variables

2 Functions of random variables 2 Functions of random variables A basic statistical model for sample data is a collection of random variables X 1,..., X n. The data are summarised in terms of certain sample statistics, calculated as

More information

MAS1302 Computational Probability and Statistics

MAS1302 Computational Probability and Statistics MAS1302 Computational Probability and Statistics April 23, 2008 3. Simulating continuous random behaviour 3.1 The Continuous Uniform U(0,1) Distribution We have already used this random variable a great

More information

System Simulation Part II: Mathematical and Statistical Models Chapter 5: Statistical Models

System Simulation Part II: Mathematical and Statistical Models Chapter 5: Statistical Models System Simulation Part II: Mathematical and Statistical Models Chapter 5: Statistical Models Fatih Cavdur fatihcavdur@uludag.edu.tr March 20, 2012 Introduction Introduction The world of the model-builder

More information

Introduction to Statistical Inference Self-study

Introduction to Statistical Inference Self-study Introduction to Statistical Inference Self-study Contents Definition, sample space The fundamental object in probability is a nonempty sample space Ω. An event is a subset A Ω. Definition, σ-algebra A

More information

STA 256: Statistics and Probability I

STA 256: Statistics and Probability I Al Nosedal. University of Toronto. Fall 2017 My momma always said: Life was like a box of chocolates. You never know what you re gonna get. Forrest Gump. Exercise 4.1 Let X be a random variable with p(x)

More information

2 (Statistics) Random variables

2 (Statistics) Random variables 2 (Statistics) Random variables References: DeGroot and Schervish, chapters 3, 4 and 5; Stirzaker, chapters 4, 5 and 6 We will now study the main tools use for modeling experiments with unknown outcomes

More information

Review: mostly probability and some statistics

Review: mostly probability and some statistics Review: mostly probability and some statistics C2 1 Content robability (should know already) Axioms and properties Conditional probability and independence Law of Total probability and Bayes theorem Random

More information

Definition 1.1 (Parametric family of distributions) A parametric distribution is a set of distribution functions, each of which is determined by speci

Definition 1.1 (Parametric family of distributions) A parametric distribution is a set of distribution functions, each of which is determined by speci Definition 1.1 (Parametric family of distributions) A parametric distribution is a set of distribution functions, each of which is determined by specifying one or more values called parameters. The number

More information

Goal: Approximate the area under a curve using the Rectangular Approximation Method (RAM) RECTANGULAR APPROXIMATION METHODS

Goal: Approximate the area under a curve using the Rectangular Approximation Method (RAM) RECTANGULAR APPROXIMATION METHODS AP Calculus 5. Areas and Distances Goal: Approximate the area under a curve using the Rectangular Approximation Method (RAM) Exercise : Calculate the area between the x-axis and the graph of y = 3 2x.

More information

Continuous Random Variables

Continuous Random Variables 1 / 24 Continuous Random Variables Saravanan Vijayakumaran sarva@ee.iitb.ac.in Department of Electrical Engineering Indian Institute of Technology Bombay February 27, 2013 2 / 24 Continuous Random Variables

More information

Continuous Random Variables and Continuous Distributions

Continuous Random Variables and Continuous Distributions Continuous Random Variables and Continuous Distributions Continuous Random Variables and Continuous Distributions Expectation & Variance of Continuous Random Variables ( 5.2) The Uniform Random Variable

More information

A Probability Primer. A random walk down a probabilistic path leading to some stochastic thoughts on chance events and uncertain outcomes.

A Probability Primer. A random walk down a probabilistic path leading to some stochastic thoughts on chance events and uncertain outcomes. A Probability Primer A random walk down a probabilistic path leading to some stochastic thoughts on chance events and uncertain outcomes. Are you holding all the cards?? Random Events A random event, E,

More information

Statistics 100A Homework 5 Solutions

Statistics 100A Homework 5 Solutions Chapter 5 Statistics 1A Homework 5 Solutions Ryan Rosario 1. Let X be a random variable with probability density function a What is the value of c? fx { c1 x 1 < x < 1 otherwise We know that for fx to

More information

Expected Values, Exponential and Gamma Distributions

Expected Values, Exponential and Gamma Distributions Expected Values, Exponential and Gamma Distributions Sections 5.2-5.4 Cathy Poliak, Ph.D. cathy@math.uh.edu Office in Fleming 11c Department of Mathematics University of Houston Lecture 14-3339 Cathy Poliak,

More information

FACULTY OF ENGINEERING AND ARCHITECTURE. MATH 256 Probability and Random Processes. 04 Multiple Random Variables

FACULTY OF ENGINEERING AND ARCHITECTURE. MATH 256 Probability and Random Processes. 04 Multiple Random Variables OKAN UNIVERSITY FACULTY OF ENGINEERING AND ARCHITECTURE MATH 256 Probability and Random Processes 04 Multiple Random Variables Fall 2012 Yrd. Doç. Dr. Didem Kivanc Tureli didem@ieee.org didem.ivanc@oan.edu.tr

More information

Chapter 3: Random Variables 1

Chapter 3: Random Variables 1 Chapter 3: Random Variables 1 Yunghsiang S. Han Graduate Institute of Communication Engineering, National Taipei University Taiwan E-mail: yshan@mail.ntpu.edu.tw 1 Modified from the lecture notes by Prof.

More information

BMIR Lecture Series on Probability and Statistics Fall 2015 Discrete RVs

BMIR Lecture Series on Probability and Statistics Fall 2015 Discrete RVs Lecture #7 BMIR Lecture Series on Probability and Statistics Fall 2015 Department of Biomedical Engineering and Environmental Sciences National Tsing Hua University 7.1 Function of Single Variable Theorem

More information

Chapter 2. Some Basic Probability Concepts. 2.1 Experiments, Outcomes and Random Variables

Chapter 2. Some Basic Probability Concepts. 2.1 Experiments, Outcomes and Random Variables Chapter 2 Some Basic Probability Concepts 2.1 Experiments, Outcomes and Random Variables A random variable is a variable whose value is unknown until it is observed. The value of a random variable results

More information

Chapter 1: Revie of Calculus and Probability

Chapter 1: Revie of Calculus and Probability Chapter 1: Revie of Calculus and Probability Refer to Text Book: Operations Research: Applications and Algorithms By Wayne L. Winston,Ch. 12 Operations Research: An Introduction By Hamdi Taha, Ch. 12 OR441-Dr.Khalid

More information

Recap. Probability, stochastic processes, Markov chains. ELEC-C7210 Modeling and analysis of communication networks

Recap. Probability, stochastic processes, Markov chains. ELEC-C7210 Modeling and analysis of communication networks Recap Probability, stochastic processes, Markov chains ELEC-C7210 Modeling and analysis of communication networks 1 Recap: Probability theory important distributions Discrete distributions Geometric distribution

More information

Probability Models. 4. What is the definition of the expectation of a discrete random variable?

Probability Models. 4. What is the definition of the expectation of a discrete random variable? 1 Probability Models The list of questions below is provided in order to help you to prepare for the test and exam. It reflects only the theoretical part of the course. You should expect the questions

More information

1 Random Variable: Topics

1 Random Variable: Topics Note: Handouts DO NOT replace the book. In most cases, they only provide a guideline on topics and an intuitive feel. 1 Random Variable: Topics Chap 2, 2.1-2.4 and Chap 3, 3.1-3.3 What is a random variable?

More information

Common ontinuous random variables

Common ontinuous random variables Common ontinuous random variables CE 311S Earlier, we saw a number of distribution families Binomial Negative binomial Hypergeometric Poisson These were useful because they represented common situations:

More information

DS-GA 1002 Lecture notes 2 Fall Random variables

DS-GA 1002 Lecture notes 2 Fall Random variables DS-GA 12 Lecture notes 2 Fall 216 1 Introduction Random variables Random variables are a fundamental tool in probabilistic modeling. They allow us to model numerical quantities that are uncertain: the

More information

Continuous Random Variables

Continuous Random Variables MATH 38 Continuous Random Variables Dr. Neal, WKU Throughout, let Ω be a sample space with a defined probability measure P. Definition. A continuous random variable is a real-valued function X defined

More information

Chapter 2. Random Variable. Define single random variables in terms of their PDF and CDF, and calculate moments such as the mean and variance.

Chapter 2. Random Variable. Define single random variables in terms of their PDF and CDF, and calculate moments such as the mean and variance. Chapter 2 Random Variable CLO2 Define single random variables in terms of their PDF and CDF, and calculate moments such as the mean and variance. 1 1. Introduction In Chapter 1, we introduced the concept

More information

Chapter 2: Random Variables

Chapter 2: Random Variables ECE54: Stochastic Signals and Systems Fall 28 Lecture 2 - September 3, 28 Dr. Salim El Rouayheb Scribe: Peiwen Tian, Lu Liu, Ghadir Ayache Chapter 2: Random Variables Example. Tossing a fair coin twice:

More information

Each element of this set is assigned a probability. There are three basic rules for probabilities:

Each element of this set is assigned a probability. There are three basic rules for probabilities: XIV. BASICS OF ROBABILITY Somewhere out there is a set of all possile event (or all possile sequences of events which I call Ω. This is called a sample space. Out of this we consider susets of events which

More information

Distributions of Functions of Random Variables

Distributions of Functions of Random Variables STAT/MATH 395 A - PROBABILITY II UW Winter Quarter 217 Néhémy Lim Distributions of Functions of Random Variables 1 Functions of One Random Variable In some situations, you are given the pdf f X of some

More information

Random variable X is a mapping that maps each outcome s in the sample space to a unique real number x, < x <. ( ) X s. Real Line

Random variable X is a mapping that maps each outcome s in the sample space to a unique real number x, < x <. ( ) X s. Real Line Random Variable Random variable is a mapping that maps each outcome s in the sample space to a unique real number, <

More information

PROBABILITY DISTRIBUTIONS

PROBABILITY DISTRIBUTIONS Review of PROBABILITY DISTRIBUTIONS Hideaki Shimazaki, Ph.D. http://goo.gl/visng Poisson process 1 Probability distribution Probability that a (continuous) random variable X is in (x,x+dx). ( ) P x < X

More information

Random Variate Generation

Random Variate Generation CPSC 405 Random Variate Generation 2007W T1 Handout These notes present techniques to generate samples of desired probability distributions, and some fundamental results and techiques. Some of this material

More information

Random Variables and Their Distributions

Random Variables and Their Distributions Chapter 3 Random Variables and Their Distributions A random variable (r.v.) is a function that assigns one and only one numerical value to each simple event in an experiment. We will denote r.vs by capital

More information

Continuous Expectation and Variance, the Law of Large Numbers, and the Central Limit Theorem Spring 2014

Continuous Expectation and Variance, the Law of Large Numbers, and the Central Limit Theorem Spring 2014 Continuous Expectation and Variance, the Law of Large Numbers, and the Central Limit Theorem 18.5 Spring 214.5.4.3.2.1-4 -3-2 -1 1 2 3 4 January 1, 217 1 / 31 Expected value Expected value: measure of

More information

n(1 p i ) n 1 p i = 1 3 i=1 E(X i p = p i )P(p = p i ) = 1 3 p i = n 3 (p 1 + p 2 + p 3 ). p i i=1 P(X i = 1 p = p i )P(p = p i ) = p1+p2+p3

n(1 p i ) n 1 p i = 1 3 i=1 E(X i p = p i )P(p = p i ) = 1 3 p i = n 3 (p 1 + p 2 + p 3 ). p i i=1 P(X i = 1 p = p i )P(p = p i ) = p1+p2+p3 Introduction to Probability Due:August 8th, 211 Solutions of Final Exam Solve all the problems 1. (15 points) You have three coins, showing Head with probabilities p 1, p 2 and p 3. You perform two different

More information

Joint Probability Distributions and Random Samples (Devore Chapter Five)

Joint Probability Distributions and Random Samples (Devore Chapter Five) Joint Probability Distributions and Random Samples (Devore Chapter Five) 1016-345-01: Probability and Statistics for Engineers Spring 2013 Contents 1 Joint Probability Distributions 2 1.1 Two Discrete

More information

Stat 35, Introduction to Probability.

Stat 35, Introduction to Probability. Stat 35, Introduction to Probability. Outline for the day: 1. Harman/Negreanu and running it twice. 2. Uniform random variables. 3. Exponential random variables. 4. Normal random variables. 5. Functions

More information

Chapter 4. Continuous Random Variables 4.1 PDF

Chapter 4. Continuous Random Variables 4.1 PDF Chapter 4 Continuous Random Variables In this chapter we study continuous random variables. The linkage between continuous and discrete random variables is the cumulative distribution (CDF) which we will

More information

Expected Values, Exponential and Gamma Distributions

Expected Values, Exponential and Gamma Distributions Expected Values, Exponential and Gamma Distributions Sections 5.2 & 5.4 Cathy Poliak, Ph.D. cathy@math.uh.edu Office in Fleming 11c Department of Mathematics University of Houston Lecture 13-3339 Cathy

More information

Random Signals and Systems. Chapter 3. Jitendra K Tugnait. Department of Electrical & Computer Engineering. Auburn University.

Random Signals and Systems. Chapter 3. Jitendra K Tugnait. Department of Electrical & Computer Engineering. Auburn University. Random Signals and Systems Chapter 3 Jitendra K Tugnait Professor Department of Electrical & Computer Engineering Auburn University Two Random Variables Previously, we only dealt with one random variable

More information

ECE 302 Solution to Homework Assignment 5

ECE 302 Solution to Homework Assignment 5 ECE 2 Solution to Assignment 5 March 7, 27 1 ECE 2 Solution to Homework Assignment 5 Note: To obtain credit for an answer, you must provide adequate justification. Also, if it is possible to obtain a numeric

More information

EE 302 Division 1. Homework 6 Solutions.

EE 302 Division 1. Homework 6 Solutions. EE 3 Division. Homework 6 Solutions. Problem. A random variable X has probability density { C f X () e λ,,, otherwise, where λ is a positive real number. Find (a) The constant C. Solution. Because of the

More information

STAT 430/510 Probability Lecture 12: Central Limit Theorem and Exponential Distribution

STAT 430/510 Probability Lecture 12: Central Limit Theorem and Exponential Distribution STAT 430/510 Probability Lecture 12: Central Limit Theorem and Exponential Distribution Pengyuan (Penelope) Wang June 15, 2011 Review Discussed Uniform Distribution and Normal Distribution Normal Approximation

More information

1 Introduction. Systems 2: Simulating Errors. Mobile Robot Systems. System Under. Environment

1 Introduction. Systems 2: Simulating Errors. Mobile Robot Systems. System Under. Environment Systems 2: Simulating Errors Introduction Simulating errors is a great way to test you calibration algorithms, your real-time identification algorithms, and your estimation algorithms. Conceptually, the

More information

Distributions of Functions of Random Variables. 5.1 Functions of One Random Variable

Distributions of Functions of Random Variables. 5.1 Functions of One Random Variable Distributions of Functions of Random Variables 5.1 Functions of One Random Variable 5.2 Transformations of Two Random Variables 5.3 Several Random Variables 5.4 The Moment-Generating Function Technique

More information

STAT 479: Short Term Actuarial Models

STAT 479: Short Term Actuarial Models STAT 479: Short Term Actuarial Models Jianxi Su, FSA, ACIA Purdue University, Department of Statistics Week 1. Some important things about this course you may want to know... The course covers a large

More information

Fourier Sin and Cos Series and Least Squares Convergence

Fourier Sin and Cos Series and Least Squares Convergence Fourier and east Squares Convergence James K. Peterson Department of Biological Sciences and Department of Mathematical Sciences Clemson University May 7, 28 Outline et s look at the original Fourier sin

More information

Northwestern University Department of Electrical Engineering and Computer Science

Northwestern University Department of Electrical Engineering and Computer Science Northwestern University Department of Electrical Engineering and Computer Science EECS 454: Modeling and Analysis of Communication Networks Spring 2008 Probability Review As discussed in Lecture 1, probability

More information

Lecture 5: Moment generating functions

Lecture 5: Moment generating functions Lecture 5: Moment generating functions Definition 2.3.6. The moment generating function (mgf) of a random variable X is { x e tx f M X (t) = E(e tx X (x) if X has a pmf ) = etx f X (x)dx if X has a pdf

More information

STAT2201. Analysis of Engineering & Scientific Data. Unit 3

STAT2201. Analysis of Engineering & Scientific Data. Unit 3 STAT2201 Analysis of Engineering & Scientific Data Unit 3 Slava Vaisman The University of Queensland School of Mathematics and Physics What we learned in Unit 2 (1) We defined a sample space of a random

More information

Independent random variables

Independent random variables Will Monroe July 4, 017 with materials by Mehran Sahami and Chris Piech Independent random variables Announcements: Midterm Tomorrow! Tuesday, July 5, 7:00-9:00pm Building 30-105 (main quad, Geology Corner)

More information

Random Variables. Cumulative Distribution Function (CDF) Amappingthattransformstheeventstotherealline.

Random Variables. Cumulative Distribution Function (CDF) Amappingthattransformstheeventstotherealline. Random Variables Amappingthattransformstheeventstotherealline. Example 1. Toss a fair coin. Define a random variable X where X is 1 if head appears and X is if tail appears. P (X =)=1/2 P (X =1)=1/2 Example

More information

Probability and Statistics Concepts

Probability and Statistics Concepts University of Central Florida Computer Science Division COT 5611 - Operating Systems. Spring 014 - dcm Probability and Statistics Concepts Random Variable: a rule that assigns a numerical value to each

More information

Continuous Distributions

Continuous Distributions Continuous Distributions 1.8-1.9: Continuous Random Variables 1.10.1: Uniform Distribution (Continuous) 1.10.4-5 Exponential and Gamma Distributions: Distance between crossovers Prof. Tesler Math 283 Fall

More information

8.2. strong Markov property and reflection principle. These are concepts that you can use to compute probabilities for Brownian motion.

8.2. strong Markov property and reflection principle. These are concepts that you can use to compute probabilities for Brownian motion. 62 BROWNIAN MOTION 8.2. strong Markov property and reflection principle. These are concepts that you can use to compute proailities for Brownian motion. 8.2.. strong Markov property. a) Brownian motion

More information

CSE 312, 2017 Winter, W.L. Ruzzo. 7. continuous random variables

CSE 312, 2017 Winter, W.L. Ruzzo. 7. continuous random variables CSE 312, 2017 Winter, W.L. Ruzzo 7. continuous random variables The new bit continuous random variables Discrete random variable: values in a finite or countable set, e.g. X {1,2,..., 6} with equal probability

More information

E[X n ]= dn dt n M X(t). ). What is the mgf? Solution. Found this the other day in the Kernel matching exercise: 1 M X (t) =

E[X n ]= dn dt n M X(t). ). What is the mgf? Solution. Found this the other day in the Kernel matching exercise: 1 M X (t) = Chapter 7 Generating functions Definition 7.. Let X be a random variable. The moment generating function is given by M X (t) =E[e tx ], provided that the expectation exists for t in some neighborhood of

More information