In: Economics
Albert's utility function is U(I) = 100I2 , where I is income.
Stock I generates net-payoffs of $80 with probability 0.3, $100 with probability 0.4; and $120 with probability 0.3. Stock II generates net-payoffs of $80 with probability 0.1, $100 with probability 0.8; and $120 with probability 0.1.
(i) Which stock should Albert select, I or II?
(ii) What general point about risk-loving preferences have your illustrated?
(i)
Albert will choose an option which gives him higher Expected Utiltiy EU
EU from Stock I = 0.3U(80) + 0.4U(100) + 0.3*U(120)
= 0.3(100*80*80) + 0.4*100*100*100 + 0.3*100*120*120
= 192000 + 400000 + 432000
= 1024000
EU from Stock II = 0.1U(80) + 0.8U(100) + 0.1*U(120)
= 0.1(100*80*80) + 0.8*100*100*100 + 0.1*100*120*120
= 64000 + 800000 + 144000
= 1008000
EU from Stock II < EU from Stock If
So, Albert will choose Stock I.
ii)
U = 100I2
dU/dI = 200I
d2U/dI2 = 200 > 0
So, the utility function is convex. So, the risk loving person has the convex preferences. More risk implies more expected utility.