week 4 uncertainty and risk, behavioral econ Flashcards
To make things easier, in economics we call the list of outcomes and
probabilities a?
Lottery
Expected utility
U(L) = π1u(c1) + π2u(c2) + … + πnu(cn)
where u(c) represents how much the consumer enjoys outcome c, and πi is the probability of state i.
is expected utility ordinal or cardinal? and what transformations can be made?
cardinal, as a monotonic transformation will not necessarily represent the same prefernces. So only positive affine transformations can be made.
Independence Assumption
states that, if two lotteries provide the same utility in one state of nature, consumer’s choice is independent of that state.
expected value
probability of an event occuring.
= π1c1 + π2c2 + … + πncn
risk averse vs risk lover vs risk neutral
1- risk averse is against taking risks and has a concave curve. prefer to get a smaller amount for sure than risk a larger amount.
2- has a convex curve, happy to risk being paid very little if this comes wih a possibiblity of coming with alot.
3- you are indifferent, given they have the same expected value.
The consumer is risk averse if being paid for sure the average outcome of the lottery is better than playing the lottery. what shows this.
u(π1c1 + π2c2) (expected value) > π1u(c1) + π2u(c2) (expected utility)
The consumer is risk lover if playing the lottery is better than being paid for sure
its average outcome. what shows this?
u(π1c1 + π2c2) (expected value) < π1u(c1) + π2u(c2) (expected utility)
certainty equivalent
is the amount of “sure” cash that makes an individual indifferent between the CE amount and the Lottery.
CE → U(CE) = E[U(L)]
Risk Premium (RP)
is the amount that the individual is willing to give up in order to avoid the gamble
RP = Expected Value − CE
allais paradox
Notice if p1 ≻ p2 then:
u(1000000) > .01u(0) + .89u(1000000) + .1u(3000000)
which implies:
.11u(1000000) − .01u(0) > .1u(3000000)
add .9u(0) to both sides gives:
.11u(1000000) + .89u(0) > .1u(3000000) + .9u(0)
which implies
p4 ≻ p3
Why is this an issue?
This violates the independence axiom!