possible error in CT6 Chapter 1 (Decision Theory)?

Hi all,

I'm doing the exam-style question in CT6 Chapter 1 (Decision Theory) and am wondering if there are any mistakes in the solutions.

It's the question where we're given the loss function

O1 O2 O3
D1 23 34 16
D2 30 19 18
D3 23 27 20
D4 32 19 19

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For part (i), state which decision can be discounted immediately. I came up with 2 answers, D2 or O3, because D4 dominates D2 (losses are larger) or O2 dominates O3 (gains are larger).

yet the solns only say D2?



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Secondly, part (ii) "determine the minimax solution to the problem" - doesn't say whether it's for player A, player B, or *both* player A and B. Does that make sense? The minimax solution is presented as being D3, but that's only a decision that player B can make.

Would appreciate any light that can be shed on this! Thanks in advance!

Also... if anyone is looking for a CT6 buddy to bounce ideas off, PM me! I need more motivation....

 

Hi MissAussie

This question is an example of the 'statistician vs nature' scenario as opposed to a two player game. Therefore, there is only one player that has a decision (ie you the statistician, where the decisions are usually labelled 'd') The other 'player' is the force of nature or whatever they call it (haven't looked at these notes for a while!).

Hope that helps

 

thanks! I never thought of that! I never considered the fact that it was a 1-person game, not a 2-person game. I'll have to read the full question again, but I don't think it was explicitly mentioned.

How confusing given that we also did study 2-people games... the question should be made clearer.

 

It probably wasn't mentioned but if I recall correctly, all of the past paper questions are of this type so consider this the default.

I can't remember a question on 2 player games so you'll soon forget about them when it comes to revising! Actually, all the past paper questions on this chapter are very easy... shame about the rest of the course