• We are pleased to announce that the winner of our Feedback Prize Draw for the Winter 2024-25 session and winning £150 of gift vouchers is Zhao Liang Tay. Congratulations to Zhao Liang. If you fancy winning £150 worth of gift vouchers (from a major UK store) for the Summer 2025 exam sitting for just a few minutes of your time throughout the session, please see our website at https://www.acted.co.uk/further-info.html?pat=feedback#feedback-prize for more information on how you can make sure your name is included in the draw at the end of the session.
  • Please be advised that the SP1, SP5 and SP7 X1 deadline is the 14th July and not the 17th June as first stated. Please accept out apologies for any confusion caused.

Chapter 8 Practice questions

A

Aisha

Member
In Question 8.5(iv) of Chapter 8 Practice Questions, how is it that the female smokers have a higher risk of heart attack than female non-smokers , shouldn't it be other way around, as z*beta value is negative for the former and Zero for the latter
 
Because the "Sex x smoking" covariate is in addition to the sex covariate and the smoking covariate, so for a 50 year smoking female, the value of each of these three covariates is equal to one. But for all males and non-smoker female, the "Sex x smoking" covariate is equal to zero. Hence it's baseline hazard multiplied by exp(-0.15) for female smoker and baseline hazard multiplied by exp(-0.4) for female non-smoker (and note that exponential of negative number is smaller than one).
 
You must log in or register to reply here.
Back
Top