Economics question
(i)State the form of the hazard function for the Cox Regression Model, defining all the terms used. (ii)State two advantages of the Cox Regression Model.
Susanna is studying for an on-line test. She has collected data on past attempts at the test and has fitted a Cox Regression Model to the success rate using three covariates:
Employment Z1 = 0 if an employee, and 1 if self-employed.
Attempt Z2 = 0 if first attempt, and 1 if subsequent attempt.
Study time Z3 = 0 if no study time taken, and 1 if study time taken.
Having analysed the data Susanna estimates the parameters as:
Employment 0.4
Attempt -0.2
Study time 1.15
Bill is an employee. He has taken study time and is attempting the test for the second time. Ben is self-employed and is attempting the test for the first time without taking study time.
(iii)Calculate how much more or less likely Ben is to pass, compared with Bill.
Susanna subsequently discovers that the effect of the number of attempts is different for employees and the self-employed.
(iv)Explain how the model could be adjusted to take this into account.
Sample Solutions
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Phasellus hendrerit. Pellentesque aliquet nibh nec urna. In nisi neque, aliquet vel, dapibus id, mattis vel, nisi. Sed pretium, ligula sollicitudin laoreet viverra, tortor libero sodales leo, eget blandit nunc tortor eu nibh. Nullam mollis. Ut justo. Suspendisse potenti.
Get sample solution
Sed egestas, ante et vulputate volutpat, eros pede semper est, vitae luctus metus libero eu augue. Morbi purus libero, faucibus adipiscing, commodo quis, gravida id, est. Sed lectus. Praesent elementum hendrerit tortor. Sed semper lorem at felis. Vestibulum volutpat, lacus a ultrices sagittis, mi neque euismod dui, eu pulvinar nunc sapien ornare nisl. Phasellus pede arcu, dapibus eu, fermentum et, dapibus sed, urna.
Morbi interdum mollis sapien. Sed ac risus. Phasellus lacinia, magna a ullamcorper laoreet, lectus arcu pulvinar risus, vitae facilisis libero dolor a purus. Sed vel lacus. Mauris nibh felis, adipiscing varius, adipiscing in, lacinia vel, tellus. Suspendisse ac urna. Etiam pellentesque mauris ut lectus. Nunc tellus ante, mattis eget, gravida vitae, ultricies ac, leo. Integer leo pede, ornare a, lacinia eu, vulputate vel, nisl.
Suspendisse mauris. Fusce accumsan mollis eros. Pellentesque a diam sit amet mi ullamcorper vehicula. Integer adipiscing risus a sem. Nullam quis massa sit amet nibh viverra malesuada. Nunc sem lacus, accumsan quis, faucibus non, congue vel, arcu. Ut scelerisque hendrerit tellus. Integer sagittis. Vivamus a mauris eget arcu gravida tristique. Nunc iaculis mi in ante. Vivamus imperdiet nibh feugiat est.
Ut convallis, sem sit amet interdum consectetuer, odio augue aliquam leo, nec dapibus tortor nibh sed augue. Integer eu magna sit amet metus fermentum posuere. Morbi sit amet nulla sed dolor elementum imperdiet. Quisque fermentum. Cum sociis natoque penatibus et magnis xdis parturient montes, nascetur ridiculus mus. Pellentesque adipiscing eros ut libero. Ut condimentum mi vel tellus. Suspendisse laoreet. Fusce ut est sed dolor gravida convallis. Morbi vitae ante. Vivamus ultrices luctus nunc. Suspendisse et dolor. Etiam dignissim. Proin malesuada adipiscing lacus. Donec metus. Curabitur gravida