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Unformatted text preview: Lecture 13 Chapter 3 Wednesday, October 8 th Moments The expected value of a power of a random variable is called moment (or moment around 0) First moment or Expected value E(X) Second moment E(X 2 ) Third moment E(X 3 ) and so on. Central moments Central moment is the expected value of the difference a random variable and its expected value (or mean) to a power. It is also called moment about the mean. Second central moment : (or Variance) Third central moment : ( ) ( ) 2 E X ( ) ( ) 3 E X Moments and Central Moments Moments and central moments are useful because they give us useful information regarding the distribution of a random variable. Until now we know how to find the mean and the variance using moments and central moments. Another useful measure is skewness (see Chapter 1). Skewness Skewness measures the departure from symmetry....
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This note was uploaded on 09/23/2009 for the course STAT 318 taught by Professor Staff during the Fall '08 term at Pennsylvania State University, University Park.
 Fall '08
 staff
 Probability

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