16 Smart/Gitman/Joehnk • Fundamentals of Investing, Thirteenth Edition
c. Standard deviation:
p p
i=1
s (r= – ¸ –
å2
) ( 1)
n
r n
2 2 2
222
2 2 2 2 2 2
[(17.6% 15.5%) (16.4% 15.5%) (16.0% 15.5%)
[(15.2% 15.5%) (14.0% 15.5%) (13.6% 15.5%) ]
6 1
[(2.1%) (.9%) (.5%) ( .3%) ( 1.5%) ( 1.9%) ]
5
(4.41% .81% .25% .09% 2.25% 3.61%)
5
11.42
5
p
p
p
p
s
s
s
s
= – + – + –
+ – + – + –
–
+ + + – + – + –
=
+ + + + +
=
= = 2.284 1.511=
d. The assets are negatively correlated. Asset L produces its highest returns when Asset M’s returns
are lowest and vice versa.
e. By combining these two negatively correlated assets, overall portfolio risk is reduced.
5.4
Asset LWeight W rAsset MWeight W r
Expected
Portfolio Return
rp
2018 14% 60% 8.40% 20% 40% 8.00% 16.40%
2019 14% 60% 8.40% 18% 40% 7.20% 15.60%
Return Avg. Return Difference Squared
16.40% 15.70% 0.70 0.49
The average return is almost the same in each case (15.47 versus 15.7), but the standard deviation is
much lower in this portfolio because less weight is given to the more variable asset.
5.5 a. Average portfolio return:
n
p j j
j 1
r w k
=
= ´
å
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