SECTION C: ANALYTICAL REASONING AND
DECISION MAKING
Read the following and choose the best alternative
(Questions 86-89):
Decisions are
often 'risky' in the sense that their outcomes are not known with certainty.
Presented with a choice between a risky prospect that offers a 50 percent
chance to win $200 (Otherwise nothing) and an alternative of receiving $100 for
sure, most people prefer the sure gain over the gamble, although the two
prospects have the same expected value. (Expected value is the sum of possible
outcomes weighted by their probability of occurrence.) Preference for a sure
outcome over a risky prospect of equal expected value is called risk averse;
indeed, people tend to be risk averse when choosing between prospects with
positive outcomes. The tendency towards risk aversion can be explained by the
notion of diminishing sensitivity, first formalized by Daniel Bernoulli in
1738. Just as the impact of a candle is greater when it is brought into a dark
room then into a room that is well lit so, suggested Bernoulli, the utility resulting
from a small increase in wealth will be inversely proportional to the amount of
wealth already in one's possession. It has since been assumed that people have
a subjective utility function, and that preferences should be described using
expected utility instead of expected value. According to expected utility, the
worth of a gamble offering a 50 percent chance to win $200 (otherwise nothing)
is 0.50*u($200), where u is the person's concave utility function. (A function
is concave or convex if a line joining two points on the curve lies entirely
below or above the curve, respectively). It follows from a concave function that
the subjective value attached to a gain of $100 is more than 50 percent of the
value attached to a gain of $200, which entails preference for the sure $100
gain and, hence, risk aversion.
Consider now a
choice between losses. When asked to choose between a prospect that offers a 50
percent chance to lose $200 (otherwise nothing) and the alternative of losing
$100 for sure, most people prefer to take an even chance at losing $200 or
nothing over a sure $100 loss. This is because diminishing sensitivity applies
to negative as well as to positive outcomes: the impact of an initial $100 loss
is greater than that of the next $100. This results in a convex function for
losses and a preference for risky prospects over sure outcomes of equal
expected value, called risk seeking. With the exception of prospects
that involve very small probabilities, risk aversion is generally observed in
choices involving gains, whereas risk seeking tends to hold in choices
involving losses.
Based on the above
passage, analyse the decision situations faced by three persons: Babu, Babitha
and Bablu.
86. Suppose instant
and further utility of each unit of gain is same for Babu. Babu has decided to
play as many times as possible, before he dies. He expected to live for another
50 years. A game does not last more than ten seconds. Babu is confused which
theory to trust for making decision and seeks help of renowed decision making
consultant: Roy Associates. what should be Roy Associates' advice to Babu?
A. Babu can decide on the basis of Expected Value
hypothesis.
B. Babu should decide on the basis
of Expected Utility hypothesis.
C. "Mr.Babu, I'm redundant".
D. A and B
E. A, B and C
Solution:
From
the given games it is clear that the expected value is same in all options i.e.
0.1 ´ $1000
= 0.25 ´ $400 =
0.5 ´ $200 =
1 ´ $100
It is
given that the instant and further utility of each unit of gain is same for
Babu.
Let us
assume that expected utility is 0.8 for Babu for each unit of gain.
\ The
expected utility is also equal.
i.e.
0.1 ´ $1000 ´ 0.8 = 0.25 ´ $400 ´ 0.8 = 0.5 ´ $200 ´ 0.8 = 1 ´ $100 ´ 0.8
Hence,
either theory is going to be the same. Choice (C)
87. Babitha played a
game wherein she had three options with following probabilities: 0.4, 0.5 and
0.8. The gains from three outcomes are likely to be $100, $80 and $50. An
expert has pointed out that Babitha is a risk taking person. According to
expected utility hypotheis, which option is Babitha most likely to favour?
A. First
B. Second
C. Third
D. Babitha would be indifferent to
all three actions.
E. None of the above.
Solution:
Since
Babita is a risk taking person, the expected value function is convex. i.e. she
prefers riskier prospect over sure or less risky prospect. Hence, she would
most likely to favour the first option. Choice
(A)
88. Continuing with
previous question, suppose Babitha can only play one more game, which theory
would help in arriving at better decision?
A. Expected
Value.
B. Expected
Utility.
C. Both
theories will give same results.
D. None
of the two.
E. Data is insufficient to answer
the question.
Solution:
Since,
Babita is risk seeking, she would go for higher gain with less probability,
expected value theory does not apply here, because expected value is equal in
all options. Since Babita is not going for sure gains, it is clear that she is
going by utility function. Choice (B)
89. Bablu had four
options with probability of 0.1, 0.25, 0.5 and 1. The gains associated with
each options are: $1000, $400, $200 and $100 respectively. Bablu chose the
first option. As per expected value hypothesis:
A. Bablu
is risk taking.
B. Expected
value function is concave.
C. Expected
value function is convex.
D. It does not matter which option
should Babu choose.
E. None of above.
Solution:
Bablu has
chosen the option which gives highest gain but has a low probability. It means
that he preferred a risky prospect over sure outcome, the fourth option. Hence,
He is risk taking. Choice
(A)