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Unformatted text preview: c Kendra Kilmer October 27, 2011 Section 8.2 - Expected Value Example 1 : Records kept by the chief dietitian at the university caferteria over a 25-wk period show the following weekly consumption of milk (in gallons): Milk 200 201 202 203 204 Weeks 4 6 8 5 2 Find the average number of gallons of milk consumed per week in the cafeteria. Definition : Let X denote a random variable that assumes the values x 1 , x 2 ,..., x n , with associated probabilites p 1 , p 2 ,..., p n , respectively. Then the expected value of X , E ( X ) , is given by: E ( X ) = x 1 p 1 + x 2 p 2 + x n p n Example 2: Referring to Example 1, let the random variable X denote the number of gallons of milk consumed in a week at the cafeteria. a) Find the probability distribution of X . b) Compute E ( X ) c) Draw a histogram for the random variable X Note : If we think of placing the histogram on a see-saw, the expected value occurs where we would put the fulcrum to balance it....
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- Fall '08