# Question: an investors utility function for money bernoulli utility function is...

###### Question details

An investor's utility function for money (Bernoulli utility
function) is the square root of money: u(x)=√x. Her decision making
can be modeled by assuming that she maximizes her expected utility.
Her current wealth is 100. (All quantities are in hundreds of
dollars.)

She has the opportunity to buy a security that either pays 8
(the "good outcome") or loses 1 (the "bad outcome"). She can buy as
many units as she wishes. For example, if she buys 5 units, she
gets 40 in the good outcomes, but loses 5 in the bad outcome. The
probability of the good outcome is 0.2, and the probability of the
bad outcome is 0.8.

In answering the questions below, you may use Excel to find
your answers, if you wish.

Will she buy any of this security? If yes, how much
exactly?

If her wealth were 150, would she buy any of this security? If
yes, how much?

If her wealth were 200, would she buy any of this security? If
yes, how much?

Suppose that a tax of 50% is imposed on this security. This
means that whenever she gains 8 from the security, she gets to keep
only 4. However, whenever she loses 1, she actually gets back 0.5,
i.e. she only loses 0.5 (because her capital loss is tax
deductible). If her initial wealth is 200, will she buy more or
less of this security than in question 3?