Q&A Bank Question 1.6

[Purp1euk]

I am having a go at a tricky question from the Q&A bank on loss and decision functions (i.e. similar to the previous exam question on chilli's from April 2010).

However I am struggling with the calculation of some of the loss functions in part (ii), and my main issue centres around why P( a2 | Theta_1=1/4) = 3/4. Would anyone be able to explain this in a little more detail?

I also don't understand why, of the nine decision functions in part (ii), some decisions are repeated but decisions such as choosing theta to be 0.75 if x=0 and 0.25 if x=1 are missing.

If I get my head around this I think this will all make a lot more sense!

 

[Purp1euk]

I note that the first part of my query is similar to an earlier forum question and I think this answers why:

http://www.acted.co.uk/forums/showthread.php?t=8726

However I would welcome any thoughts on the second part (I.e. why are some decision functions repeated and some possible decision functions excluded)?

 

[suraj]

I also don't understand why, of the nine decision functions in part (ii), some decisions are repeated but decisions such as choosing theta to be 0.75 if x=0 and 0.25 if x=1 are missing.

I don't see any decision function being repeated or missing. The one which you're saying is missing is d8(x)
Check again!

 

[Sendo]

I am also struggling with this question. I notice Purp1euk posted a link for the first part of the query, but it doesn't work anymore. Please help.

 

[John Lee]

I am also struggling with this question. I notice Purp1euk posted a link for the first part of the query, but it doesn't work anymore. Please help.

You just do a search on the forums. By searching the CT6 thread titles for "CT6 Q&A 1.6 decision" I got this one:

https://www.acted.co.uk/forums/index.php?threads/decision-theory.10072/