 # Random Variables and Stochastic Processes 0903720 Lecture14 Dr

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Download presentation Random Variables and Stochastic Processes – 0903720 Lecture#14 Dr. Ghazi Al Sukkar Email: ghazi. [email protected] edu. jo Office Hours: Refer to the website Course Website: http: //www 2. ju. edu. jo/sites/academic/ghazi. alsukkar 1 Chapter 6 Two Functions of Two Random Variables § § § § § Joint Moments Covariance Correlation Coefficient Orthogonality Vector space of Random Variables Joint characteristic functions Moment Generating Function More on Gaussian R. V. s Central Limit Theorem 2 Joint Moments • 3      Covariance • 9   Examples of Uncorrelated and Correlated Random Variables 12 13 Interpretation of Correlation Coefficient 14  Orthoganality • 16     Vector space of Random Variables • 21  Joint characteristic functions • 23  • It is easy to show that 25 Moment Generating Function • 26 More on Gaussian R. V. s • 27   • Gaussian input Linear operator Gaussian output 30 Central Limit Theorem • 31 • we have • Consider: where we have made use of the independence of the R. V. s, but: • Then: and as since 32 • In Summary: • The central limit theorem states that a large sum of independent random variables each with finite variance tends to behave like a normal random variable. Thus the individual PDFs become unimportant to analyze the collective sum behavior. • If we model the noise phenomenon as the sum of a large number of independent random variables (e. g. : electron motion in resistor components), then this theorem allows us to conclude that noise behaves like a Gaussian R. V. 33   Discriminant • BACK 36