Utility functions: degree of risk aversion 49
u
is unique up to a strictly increasi
ng affine transformation (, i.e.
u
can
be replaced by
a+bu
for any constants
a
and
b
>0 without changing the
preference ordering of
u
)
Ä
such a transformation should not change
the measure of risk aversion!
Ä
Arrow-Pratt measure of absolute risk aversion
Ä
Risk tolerance
Ä
Arrow-Pratt measure of relative risk aversion
'' '
u u
A
−
=
A
T
1
=
'' '
*
u u
w
A
w
R
−
=
=
Single-period random cash
flows: Utility theory