# Hw07ans - STAT 408 Spring 2009 Homework#7(due Friday March...

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STAT 408 Spring 2009 Homework #7 (due Friday, March 13, by 3:00 p.m.) 1. A simple model for describing mortality in the general population in a particular country is given by the probability density function ( 29 ( 29 2 6 18 100 10 252 y y y f - = , 0 < y < 100. a) Verify that f ( y ) is a valid probability density function. 1. f ( y ) 0 for each y ; c 2. ( 29 1 = - y y f d . ( 29 ( 29 ( 29 - = - = - 1 0 2 6 100 0 2 6 18 1 252 100 10 252 x x x y y y y y f d d d = 504 2 252 0 1 9 1 8 1 2 7 1 252 9 8 7 = + - x x x = 1. c b) Based on this model, which event is more likely or A: a person dies between the ages of 70 and 80 B: a person lives past age 80? A: ( 29 ( 29 - = - 8 . 0 7 . 0 2 6 80 70 2 6 18 1 252 100 10 252 x x x y y y d d = 7 . 0 8 . 0 9 1 8 1 2 7 1 252 9 8 7 + - x x x 0.7382 – 0.4628 = 0.2754.

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B: ( 29 ( 29 - = - 0 . 1 8 . 0 2
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## This note was uploaded on 04/27/2009 for the course STAT 420 taught by Professor Stepanov during the Spring '08 term at University of Illinois at Urbana–Champaign.

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Hw07ans - STAT 408 Spring 2009 Homework#7(due Friday March...

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