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Unformatted text preview: X ]. b. Find the second moment E [ X 2 ]. c. Find the variance var[ X ]. d. Find the standard deviation . 5. (2 pts) The probability that a telephone call lasts no more that t minutes is often modeled using the following exponential CDF: F T ( t ) = ( 1-e-t 3 t otherwise Find the probability that a call duration is within 1 standard deviation of the expected call duration? (Hint: if E [ T ] is the expected value of t and is the standard deviation of t , nd the probability P [ E [ T ]- t E [ T ] + ].) 1...
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This note was uploaded on 09/07/2009 for the course ECE 302 taught by Professor Gelfand during the Fall '08 term at Purdue University-West Lafayette.
- Fall '08