• 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.

A2008 8(iv)

A

aditya

Member
Hi,

The solution gives an explanation stating that the null hypo. is true as the interval given contains zero. But the given interval is a two sided symmetric interval whereas the question was to test the hypo. against improvement(i.e one sided test)...
So do we have to calculate the one sided interval or just continue as given in the solution ?(although both give the same conclusion)
 
We don't have to test anything here, just infer from the given data.

The value of regression parameter for new tuition method (b3) is negative (-0.05). So by first looks, it does seem to have reduced the hazard rate of children giving up on their music classes.

But when we look at it's C.I. which is [-0.15,0.05], it seems to have 0 in it (which will result in unchanged hazard) and positive values as well (which will increase the hazard rather than decreasing it).

So, at 5% level of significance we cannot conclude that the "New tuition method" has decreased the hazard rate of exits..

Now suppose, if this was a 90% symmetric C.I. then surely it would've have been smaller than the 95% one.
Say if it was [-0.09,-0.01]. Now this C.I. doesn't contains 0.

So we would've written that "At 10% level of significance, it's reasonable to conclude that the 'new tuition method' seems to have increased the persistency rates or decreased the hazard rate of exits"

Hope this helps..
 
You must log in or register to reply here.
Back
Top