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An Introduction to Decision Theory

Martin Peterson

Chapter 5

Utility - all with Video Answers

Educators


Chapter Questions

01:14

Problem 1

Which preference ordering is represented by the following ordinal utility function: $u(a)=7, u(b)=3, u(c)=34, u(d)=-430, u(e)=3.76$ ?

Alkendra Singh
Alkendra Singh
Numerade Educator
01:33

Problem 2

The following function $u$ is not an ordinal utility function. Why not? $u(a)$ $=7, u(b)=3, u(c)=34, u(d)=-430, u(e)=3.76, u(e)=12$.

Saurabh Chandra
Saurabh Chandra
Numerade Educator
04:48

Problem 3

Your preferences are transitive and asymmetric, and you prefer $a$ to $b$ and $b$ to $c$. Explain why it has to be the case that you do not prefer $c$ to $a$.

Md.Daniyal Arshad
Md.Daniyal Arshad
Numerade Educator
02:36

Problem 4

Strict preferences are irreflexive, meaning that no $x$ is strictly preferred to itself. Show that asymmetry implies irreflexivity.

Supratim Pal
Supratim Pal
Numerade Educator

Problem 5

Show that negative transitivity is logically equivalent with the following claim: $x>z$ implies that, for all $y$ in $B, x>_y$ or $y>_z$.

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03:15

Problem 6

Show that if $>$ is asymmetric and negatively transitive, then $>$ is transitive.

Anurag Kumar
Anurag Kumar
Numerade Educator
01:46

Problem 7

You are indifferent between receiving $A$ for sure and a lottery that gives you $B$ with a probability of 0.9 and $C$ with a probability of 0.1 . You are also indifferent between receiving $A$ for sure and a lottery that gives you $B$ with a probability of 0.6 and $D$ with a probability of 0.4 . All of your preferences satisfy the von Neumann-Morgenstern axioms.
(a) What do you prefer most, $C$ or $D$ ?
(b) Calculate the (relative) difference in utility between $B$ and $C$, and between $B$ and $D$.
(c) If we stipulate that your utility of $B$ is 1 and your utility of $C$ is 0 , what are then your utilities of $A$ and $D$ ?

Breanna Ollech
Breanna Ollech
Numerade Educator
05:38

Problem 8

The continuity axiom employed by von Neumann and Morgenstern holds that if $A>B>C$ then there exist some probabilities $p$ and $q$ such that $A p C>$ $B>A q C$. Let $$A=\$ 10,000,001$$ and $$B=\$ 10,000,000$$, and $C=50$ years in prison. (a) Do you think it is really true that there are any values of $p$ and $q$ such that $A p C>B>A q C$ truly describes your preferences? (b) Psychological studies suggest that most people cannot distinguish between very small probabilities, i.e. that their preferences over lotteries in which there is a small probability of a very bad outcome is unaffected by exactly how small the probability is. Does this show that there is something wrong with von Neumann and Morgenstern's theory?

Rashmi Sinha
Rashmi Sinha
Numerade Educator
04:09

Problem 9

You prefer a fifty-fifty chance of winning either $$\$ 100$$ or $$\$ 10$$ to a lottery in which you win $$\$ 200$$ with a probability of $$1 / 4, \$ 50$$ with a probability of $1 / 4$, and $$\$ 10$$ with a probability of $1 / 2$. You also prefer a fifty-fifty chance of winning either $$\$ 200$$ or $$\$ 50$$ to receiving $$\$ 100$$ for sure. Are your preferences consistent with von Neumann and Morgenstern's axioms?

Heena Haldankar
Heena Haldankar
Numerade Educator
01:13

Problem 10

You somehow know that the probability is $75 \%$ that your parents will complain about the mess in your room the next time they see you. What is their utility of complaining?

Ajay Singhal
Ajay Singhal
Numerade Educator
01:13

Problem 11

You somehow know that the probability is $5 \%$ that you will tidy up your room before your parents come and visit you. What is best for you, to tidy up your room or live in a mess?

Ajay Singhal
Ajay Singhal
Numerade Educator
00:38

Problem 12

The conclusion of Exercise 5.11 may be a bit surprising - can you really find out what is best for you by merely considering what you are likely to do? For example, the probability is 0.99 that a smoker will smoke another cigarette, but it seems false to conclude that it would be better for the smoker to smoke yet another cigarette. What could the advocate of the probabilistic theory say in response to this objection?

Amy Jiang
Amy Jiang
Numerade Educator