EE250 Probability, Random Variables and Stochastic Processes Instructor: Dr. Juzi Zhao Fall 2022 Lecture 1: Course Overview Probability Models Lecture outline Course overview Instructor information Course materials Probability Models 8/19/2022 EE250: Lecture 1 2 Course Information Lectures: 8/19/2022 TuTh 3:00PM - 4:15PM Zoom link:https://sjsu.zoom.us/j/85980439008 This course will be recorded for instructional/educational purposes. The recordings will only be shared with students enrolled in the class through Canvas. The recordings will be deleted at the end of the semester EE250: Lecture 1 3 Primary Instructor: Dr. Juzi Zhao E-mail: juzi.zhao@sjsu.edu Office hours: Wednesday Office Hour 9:00-10:00am, Zoom link: https://sjsu.zoom.us/j/85478022485 Friday Office Hour 4:00-5:00pm, Zoom link: https://sjsu.zoom.us/j/86131063875 Available by appointment at other times ISA: TBD 8/19/2022 EE250: Lecture 1 4 Course materials Textbook: Probability and Random Processes for Electrical Engineering by A. Leon-Garcia, Prentice Hall, (3rd Edition). Required. Course materials such as syllabus, handouts, notes, assignments, etc. can be found on Canvas Leaning Management System course login website at http://sjsu.instructure.com. 8/19/2022 EE250: Lecture 1 5 Course policies Grading breakdown Midterm 1 (Sept 22) Midterm 2 (Nov. 3) Final exam (Dec. 9) Assignments 25 % 25 % 30 % 20 % Online open book open notes exams might use a Proctoring service such as ProctorU 8/19/2022 EE250: Lecture 1 6 Exams The final exam date is fixed. If you have 3 or more final exams in 24 hours, you can request to take a make-up final exam on Thursday, Dec. 15. Please email me to schedule the make-up exam time at least 2 weeks before Dec. 15. If you request to re-schedule the midterm exams, please let me know (by email) at least 2 weeks before the corresponding midterm exam dates (Sept. 22 and Nov. 3, respectively). I will ask the rest of class about their availability and preference. 8/19/2022 EE250: Lecture 1 7 Bonus There may be a short group quiz during some classes to check whether or not you understand some concepts covered in the class Break the class randomly into small groups Group members have discussions on the quiz questions (via Zoom breakout rooms) Randomly choose one group to share/explain their solutions to the class 8/19/2022 0.5 point as bonus to each member of the selected group if their solutions are correct EE250: Lecture 1 8 Sets A set is a collection of unique objects Here “objects” can be concrete things (people in class, schools in San Jose), or abstract things (numbers, colors) We use capital letters to denote sets The things that together make up the set are elements 8/19/2022 EE250: Lecture 1 9 Sets Two basic ways to specify a set: 1. List all the elements, separated by commas, inside a pair of braces: A={0, 1, 2, 3} 2. Give a property that specifies the elements of the set: A={x: x is an integer such that 0≤x≤3} 8/19/2022 EE250: Lecture 1 10 Building Sets Using Conditionals Mathematical rule for generating all of the elements of the set: perform the operation to the left of the vertical bar on the numbers to the right of the bar C {x 2 | x 1,2,3,4,5} D {x 2 | x 1,2,3,...} Is 10 an element of set D? Is 144 an element of set D? Is 49 an element of set C? 8/19/2022 EE250: Lecture 1 11 Sets Order in a set does not matter! {1, 2, 3} = {3, 1, 2} = {1, 3, 2} We use small letters to denote elements When x is an element of A, we denote this by: x ∈ A If y is not in a set A, we denote this as: y A The “empty” r “null” set has no elements: ∅= { } Universal set U is the set of all elements of interest in a given setting or application 8/19/2022 EE250: Lecture 1 12 Subsets A set A is a subset of another set B if every element of A is also an element of B, and we denote this as A B. Every set is a subset of U Examples {1, 9} {1, 3, 9, 11} { apple, pear} { apple, pear, banana} ∅ A for any set A A={x: x≥10} C={x:x ≥ 20} Set equality A = B A = B if and only if A 8/19/2022 B and B EE250: Lecture 1 A 13 Set Operations:Complement Definition The complement of a set A U, denoted Ac, is the set of all elements in U that are not in A. Ac = {x|x ∈ U, xA} Example: roll a six-sided die and observe the number of dots on the side facing upwards A = {1, 3, 5} “an odd roll” The complement of U is null set ∅ 8/19/2022 EE250: Lecture 1 14 Set Operations: Union Definition The union of two sets A and B, denoted A ∪ B is the set of all elements in either A or B (or both). A ∪ B = {x|x ∈ A or x ∈ B or both} Example: roll a six-sided die and observe the number of dots on the side facing upwards A = {1, 3, 5} B = {1, 2, 3} 8/19/2022 “an odd roll” “a roll of 3 or less” EE250: Lecture 1 15 Set Operations:Intersection Definition The intersection of two sets A and B, denoted A ∩ B is the set of all elements in both A and B. A ∩ B = {x|x ∈ A and x ∈ B} Example: roll a six-sided die and observe the number of dots on the side facing upwards A = {1, 3, 5} “an odd roll” B = {1, 2, 3} “a roll of 3 or less” Note: If A ∩ B = ∅, we say A and B are disjoint or mutually exclusive. 8/19/2022 EE250: Lecture 1 16 Set Operations: Difference Definition The difference of a set A U and a set B U, denoted A − B, is the set of all elements in U that are in A and are not in B. A - B = {x|x ∈ A and x B} Example: A = { 3, 4, 5, 6} B = { 3, 5} 8/19/2022 EE250: Lecture 1 17 Visualize Set Operations with Venn Diagrams U 8/19/2022 EE250: Lecture 1 18 Examples A={x: x≥10} B={2,4,6,...} (assume elements are integers) Find A ∩ B, A ∪ B, A-B, B-A, Ac , Bc 8/19/2022 EE250: Lecture 1 19 Properties Commutative properties: A ∩ B= B ∩ A, A ∪ B= B ∪ A Associative properties: A ∩ (B ∩ C)= (A ∩ B) ∩ C A ∪ (B ∪ C) = (A ∪ B) ∪ C Distributive properties: A ∪ (B ∩ C)= (A ∪ B) ∩ (A ∪ C) A ∩ (B ∪ C)= (A ∩ B) ∪ (A ∩ C) 8/19/2022 EE250: Lecture 1 20 DeMorgan’s Law (A ∪ B)c = Ac ∩ Bc (A ∩ B)c = Ac ∪ Bc 8/19/2022 EE250: Lecture 1 21 Examples A={v: |v| > 10}, B={v: v<-5}, C={v: v>0} (assume elements are integers) A ∩ B, A ∪ B,Cc,(A ∪ B) ∩ C,A ∩ B ∩ C,(A ∪ B)c 8/19/2022 EE250: Lecture 1 22 Random Experiment A random experiment to be an experiment in which the outcome varies in an unpredictable fashion when the experiment is repeated under the same conditions Random experiment is specified by stating an experimental procedure and a set of one or more measurements or observations 8/19/2022 EE250: Lecture 1 23 Examples Select a ball from an urn containing balls numbered 1 to 50. Note the number of the ball. Toss a coin three times and note the sequence of heads and tails. Toss a coin three times and note the number of heads. A block of information is transmitted repeatedly over a noisy channel until an error-free block arrives at the receiver. Count the number of transmissions required. Pick a number at random between zero and one. Measure the lifetime of a given computer memory chip in a specified environment. Determine the values of an audio signal at times T1 and T2 Pick two numbers at random between zero and one. Pick a number X at random between zero and one, then pick a number Y at random between zero and X. 8/19/2022 EE250: Lecture 1 24 Outcome and Sample Space An outcome or sample point of a random experiment as a result that cannot be decomposed into other results When we perform a random experiment, one and only one outcome occurs outcomes are mutually exclusive The sample space S of a random experiment is defined as the set of all possible outcomes Each performance of a random experiment can then be viewed as the selection at random of a single point (outcome) from S 8/19/2022 EE250: Lecture 1 25 Sample space A sample space can be finite, countably infinite, or uncountably infinite S a discrete sample space if S is countable S a continuous sample space if S is not countable 8/19/2022 EE250: Lecture 1 26 Events An event is a subset of S The event occurs if and only if the outcome of the experiment is in this subset Two events of special interest are the certain event, S, which consists of all outcomes and hence always occurs, and the impossible or null event ∅, which contains no outcomes and hence never occurs An event may consist of a single outcome An event from a discrete sample space that consists of a single outcome is called an elementary event. 8/19/2022 EE250: Lecture 1 27 Event Class A class of events is a collection (set) of events (sets) If the class C consists of the collection of sets A1, A2, A3,... Ak then C={A1, A2, A3,... Ak } 8/19/2022 EE250: Lecture 1 28