CFALA
Review:
Tips
for
using
the
TI
calculator
2/9/2015
By
David
Cary
7
CFA Society Los Angeles
13
3. USING AOS (NOT Chn):
To get to AOS, use [2
nd
] [FORMAT] and the screen
will show the decimal setting.
Use up arrow and it may say Chn or AOS. If it says
Chn, use [2
nd
] [SET] to change to AOS. If it says AOS, it is ready to go.
Then hit [CE/C] to start.
(You can switch back and forth, I use AOS)
• r
p
= r
1
w
1
+ r
2
w
2
1: 0.75
20 + 0.25
12 = 18
“no parenthesis or memories needed for calculation!”
• s
p
2
= w
1
2
s
1
2
+ w
2
2
s
2
2
+ 2
w
1
w
2
s
12
1: 0.75[x
2
]
625 + 0.25[x
2
]
196 + 2
0.75
0.25
120 = 408.81
“the variance”
5: [
x
] = 20.22 “the standard deviation si 20.22%”
• See previous bottom note if given standard deviations and/or correlations.
13
CALCULATING MEANS AND COVARIANCES OF
TWO ASSET PORTFOLIO
1
2
w
75%
25%
r
20%
12%
var
625
196
Covar
120
CFA Society Los Angeles
14
WHICH METHOD TO USE
• I like AOS. For the simpler calculations you can do them directly. For
more complicated calculations you can still use the memory or
parenthesis methods even if the calculator is in AOS mode.
• For example, I would probably do the “r
p
” calculation on the previous
page using AOS, nice and simple. But for the s
p
2
calculation, I might
use the memory method so if I messed up a calculation towards the
end of the equation, I wouldn’t have to start all over.
• If you want to use AOS mode, please check on a regular basis it is still
in AOS mode. An accidental reset may change it back to Chn.
• Not sure why you would want to but you can easily change back and
forth between AOS and Chn by using the [2
nd
] [FORMAT], then up
arrow, then [2
nd
][SET].
14
