STAT265 : Chapter 3: Random Variables: Notes done In LaTeX
22 Dec 2011
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Document Summary
A random variable is a real valued function de ned on a sample space s. Y is mapping the domain to the range. A random variable y is said to be discrete random variable if it can assume only a countable number of values. The probability distribution of a discrete r. v. is the collection of all probabilities p (k) = p (y = k) k = 1, 2, 3, . Properties of p(y=k: 0 p (y = k) 1 for all valid values of k, (cid:80) p (y = k) = 1. If y is a discrete random variable, then (cid:88) k p (y = k) = e (y ) = is called the expected value of y, or of the probability distribution of y. Five balls, numbered 1, 2, 3, 4, and 5 are placed in an urn. Two balls are randomly selected (without replacement) from the ve, and their numbers noted.
