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The Time Value of Money
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LOS a
Interest rate can be interpreted as - Required rate of return, Discount rate
or Opportunity cost
LOS b
International Fischer Relationship (approx.)
1
100
@ 10% p.a.
110
Consumption cost 107
True saving 3
Inflation
Real rate of
return
2
e
Nominal risk-free rate = Real risk-free rate + Expected inflation
Treasury bonds = Real RFR + Expected inflation
re
Corporate bonds = Real RFR + Expected inflation + Risk premium
Return on Non-investment grade bond > Return on Investment grade bond, because
risk of Non-investment grade bond > risk of Investment grade bond
Types of risks
nT
3
Liquidity
risk
Maturity
risk
Risk that borrower
will not make
promised payments
in a timely manner
Risk of receiving
less than FV for an
investment if it
must be sold for
cash quickly
Risk of volatility
of price of a bond
because of its
longer maturity
Default risk
premium
Liquidity risk
premium
Maturity risk
premium
Low default rate
=
Low DRP
Less liquidity
=
High LRP
Shorter maturity
=
Low MRP
Fi
Default
risk
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LOS c
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Calculation and interpretation of effective annual rate
The rate of interest that an investor actually earns as a result of
compounding is known as EAR
1 + (Int. rate/m)m - 1
Effective Annual Rate =
m = compounding frequencies per year
EAR on TI BA II Plus Professional - 2nd 2
LOS d
TVM with different compounding frequencies
Annual
Quarterly
Semiannual
N=1
I/Y = 13.25
PV = -100
FV = 113.25
N=1X2=2
I/Y = 13.25/2 = 6.625
PV = -100
FV = 113.68
LOS e
Monthly
N=1X4=4
I/Y = 13.25/4 = 3.3125
PV = -100
FV = 113.92
N = 1 X 12 = 12
I/Y = 13.25/12 = 1.104
PV = -100
FV = 114.08
Annuity
1
e
It is a stream of equal cash flows occurring at equal intervals.
Annuity due
re
Ordinary annuity
End mode
1
2
100
100
0
1
2
3
100
100
100
100
100
PV of perpetuity =
2
LOS f
3
nT
0
Beginning mode
1
Amortization schedule
Loan - 100,000
Fi
CF
Disc. rate
Int. rate - 10%
Tenure - 4 yrs.
Year
Opening
loan
Instalment
Interest
(Op. loan X
rate of int.)
Principal
repayment
(Inst - Int.)
Closing loan
(Op. loan Princ.
repayment)
1
100,000
31,547
10,000
21,547
78,452
2
78,452
31,547
7,845
23,701
54,751
3
54,751
31,547
5,475
26,071
28,679
4
28,679
31,547
2,868
28,679
-
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Using amort function in TI BA II plus professional
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
2nd CLR TVM (FV)
PV = -100,000 N = 4 I/Y = 10 CPT PMT = 31,547
2nd AMORT (PV)
2nd CLR WORK (CE|C)
P1 = 1
P2 = 1
BAL = 78,452
PRN = 21,547
INT = 10,000
P1 = 2
P2 = 2
3
Eg.
CFs:
PV and FV of uneven CFs
Discount rate = 10%
N = 6 years
Year 1 = −1,000 Year 2 = −500 Year 3 = 0 Year 4 = 4,000 Year 5 = 3,500 Year 6 = 2,000
re
CF
2nd CLR WORK (CE|C)
CF0 = 0
CF1 = −1,000
CF2 = −500
CF3 = 0
CF4 = 4,000
CF5 = 3,500
CF6 = 2,000
I = 10 → Enter → ↓ (down key)
CPT NPV = 4711.91
Fi
nT
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
Ÿ
e
Using CF function in TI BA II plus professional
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Discounted Cash Flow Applications
LOS a
NPV
PV of inflows − PV of outflows
IRR
Rate at which PV of inflows = PV of outflows
At IRR, NPV = 0
LOS b
Decision rule
IRR
NPV
+ve = Accept
If IRR > WACC = Accept
−ve = Reject
If IRR < WACC = Reject
Mutually exclusive projects Accept project with highest NPV
For a single project NPV and IRR rules lead to same accept/reject decision
e
If IRR > WACC, NPV =+ve
If IRR < WACC, NPV =−ve
LOS c
re
Holding period return (HPR)
Ending value − beginning value
Beginning value
Or
Ending value − 1
Beginning value
Total return
Ending value + CF received − 1
Beginning value
Time-weighted rate of return
(TWRR)
IRR
Geometric mean of HPR
Appropriate if manager has complete
control over inflows and outflows
!
Or
Money-weighted rate of return
(MWRR)
Fi
LOS d
nT
Ending value - beginning value + CF received
Beginning value
Provides better measure of manager’s
ability to select investments
TWRR is not affected by timing of the cash flows, therefore it is more preferred method of
performance measurement
! If funds are contributed to a portfolio just prior to a period of relatively poor performance,
MWRR < TWRR
! If funds are contributed to a portfolio just prior to a period of relatively high returns,
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LOS e & f
Effective earning yield
(1+3.09%)365/90- 1
= 13.13%
j
k
l
Or
3 mistakes analogy to
remember the formulas
(indicated in red)
Compounding
365 days
Investment
value as base
90
3.09%
365
12.53%
3.09
1 + 3.09%
1000
90 days
30
= 3.09%
970
Bank discount yield
12%
j
k
l
Money market yield
No Compounding
360 days
Face value as
base
3
1 − 3%
90
3.09%
360
12.36%
Fi
nT
re
e
360
No Compounding
365 days
Investment
value as base
T - bill
970
30/1000 =3%
j
k
l
Holding period yield
N = 90/365
PV = -970
FV = 1000
I/Y = 13.14 %
90
Bond equivalent yield
j
k
l
No Compounding
360 days
Investment value
as base
Statistical Concepts and Market Returns
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LOS a
1
Descriptive statistics
Inferential statistics
Used to summarize important
characteristics of large data
Used to make forecasts of
large data
Eg. Average of weekly tests
Eg. Forecast on pass or not
2
Sample
Set of all possible members of a stated group
Subset of population
CFA level 1 candidates globally
CFA level 1 candidates in class
Nominal
Ordinal
Interval
Higher level of
measurement than
nominal scales
Provides relative
ranking and
assurance that
differences
between scale
values are equal
nT
Contains least
information
Types of measurement scales
re
3
e
Population
Classification
has no
particular order
Observation is
assigned to a
category
Fi
Eg. MF’s star
rating
LOS b
Parameter
Measure used to
describe a
characteristic of a
population
Sample statistic
Weakness - Zero
doesn’t mean total
absence
Eg. Temperature
measurement
Ratio
Most refined level
of measurement
Provides ranking
and equal
differences
between scale
values
Has a true zero
point as origin
Frequency distribution Tabular presentation of statistical data
It is used to measure
a characteristic of a
sample
Data employed with a frequency
distribution may be measured using any
type of measurement scale
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LOS c
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Relative frequency and cumulative relative frequency
Interval /
class
Frequency
Cumulative
frequency
Relative frequency
Cumulative
relative frequency
10 - 15
7
7
(7/50) 14%
14%
15 - 20
12
19
(12/50) 24%
38%
20 - 25
21
40
(21/50) 42%
80%
25 - 30
10
50
(10/50) 20%
100%
Total
50
100%
Histogram and Frequency polygon
LOS d
Frequency
Interval
Interval
midpoints
Frequency polygon
re
Histogram
e
Frequency
LOS e
Measures of central tendency
1
Weighted mean
AM = 10 + 14 + 4 + 8
4
WM = 10(20%) +
14(20%) +
4(35%) +
8(25%)
WM = 8.2
Geometric mean
Harmonic mean
GM =
HM =
√1.1 X 1.14 X 1.04 X 1.08 − 1
4
1/10 + 1/14 + 1/4 +1/8
GM = 8.94
HM = 7.32
4
Fi
AM = 9
nT
Arithmetic mean
Mean
ª Sum of deviations from arithmetic mean is always zero
ª To calculate portfolio return, weighted mean is used
ª
Geometric mean is used for calculating investment returns over multiple periods
ª Harmonic mean is used to calculate average of ratios
ª Arithmetic mean > Geometric mean > Harmonic mean
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Median
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It is the midpoint of a data set
Median = [(n+1) X 50%]th observation
Data needs to be arranged in ascending order
to calculate median using above formula
1
3
2
3
Mode
4
5
6
7
8
9
Median = [(9+1) X 50%] = 5th observation
Value that occurs most frequently in a data set
A data set can have more than one mode or
even no mode
If a data set has one/two/three modes it is
said to be unimodal/bimodal/trimodal
LOS f
Quartiles, quintiles, deciles, percentiles
Quartiles
e
Distribution is
divided into
tenths
Distribution is
divided into
fifths
[(n + 1) × 25%]th
[(n + 1) × 20%]th
re
Distribution is
divided into
quarters
LOS g
Percentiles
Deciles
Quintiles
[(n + 1) × 10%]th
Distribution is
divided into
hundreds
[(n + 1) × 1%]th
nT
Measures of dispersion
Mean absolute
deviation
(MAD)
Variance
Maximum value
− minimum
value
∑|(x − x)|
n
Population variance -
Fi
Range
∑ (x − μ)2
n
Standard deviation
Population SD -
Sample SD -
Sample variance ∑ (x − x)2
n−1
Variance = σ2
SD can be calculated directly on TI BA II plus professional.
Ÿ Use DATA (2nd 7) to enter data then,
Ÿ Use STAT (2nd 8) to see SD
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LOS h
Chebyshev’s inequality
Applies to sample or population data, normal or skewed distribution
Calculated as,
1 − 1/k2
60
Eg.
70
SD = 5
where k > 1
80
Chebyshev’s inequality = 1 − 1/22
= 1 − 1/4
K = 10/SD
K=2
= 75%
Interpretation: 75% observations lie within ±2 SD of mean
LOS i
Sharpe ratio
Coefficient of variation (CV)
It is used to measure excess
return per unit of risk
It is used to measure
the risk per unit of
expected return
aka reward-to-variability
ratio
e
CV = SDx
X
SR = Portfolio return − RFR
SD of portfolio
Lower the better
re
Higher the better
Sharpe ratio
Fi
RFR
10 km
Which is more economical ?
Wrong interpretation -
25/3 = 8.33
Correct interpretation -
15/3 = 5
Sharpe ratio =
km
km
15 km
Motorcycle takes 2.2 ltrs of petrol
to cover the entire distance
10
10
RFR
nT
Motorcycle takes 3 ltrs of petrol
to cover the entire distance
✘
20/2.2 = 9.09
✓
25 − 10
3
✓
10/2.2 = 4.54 ✘
Rp − RFR
SDp
20 − 10
2.2
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LOS j
Skewness
Negatively skewed/
left skew
Positively skewed/
right skew
No skew
Normal distribution
Skewed distribution
Symmetrical
distribution
Asymmetrical
distribution
Skewness: Extent to which data is not symmetrical
Negative skew in returns distributions indicates increased risk
LOS k
re
e
Locations of mean, median and mode
Mean,
median,
mode
LOS l
Median
Median
Mean > Median > Mode
Fi
1
Mean Mode
nT
Mean = Median = Mode
Mode Mean
Mean < Median < Mode
Kurtosis
Mesokurtic
distribution
Leptokurtic
distribution
Platykurtic
distribution
Kurtosis = 3
Kurtosis > 3
Kurtosis < 3
Excess kurtosis = 0
Excess kurtosis = +ve
Excess kurtosis = -ve
Kurtosis: Measures the peakedness of a distribution
Positive kurtosis in returns distributions indicates increased risk
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3
Sample skewness - Sk = ∑(X-X)
x 1
3
SD
n
Sk > 0.5 indicates significant level of skewness
4
x 1
Sk = ∑(X-X)
4
SD
n
Excess kurtosis > 1 is considered a large value
Sample kurtosis -
LOS m
Use of arithmetic mean and geometric
mean when analyzing investment returns
Arithmetic mean return is appropriate for forecasting single period returns in future periods
Fi
nT
re
e
Geometric mean return is appropriate for forecasting future compound returns over multiple periods
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Probability Concepts
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LOS a
Random variable
Outcome
Event
Mutually
exclusive
events
Uncertain quantity/
number
Observed value
of a random
variable
An outcome or
a set of
outcomes
Events that can
not happen
together
1
LOS b
All possible events
Two defining properties of probability
è
Probability is always between 0 & 1
è
If we have mutually exclusive and exhaustive events then sum of
probabilities of those events will always be 1
2
e
Probabilities
Objective
re
Subjective
Priori
Empirical
Eg. Historical pass
rates
Least formal
method of
developing
probabilities
Determined using
formal reasoning
nT
Established by
analyzing historical
data
Involves personal
judgement
Eg. Throwing a die
= 1/6
Probability of an event in terms of odds
Fi
LOS c
Exhaustive
events
If probability of an
event is 20%
Then for 10 experiments,
success = 2 failure = 8
2/10
Odds for
Odds against
2/8
8/2
Two-to-eight
Eight-to-two
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LOS d
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Unconditional and conditional probabilities
Unconditional
Conditional
µ
Refers to probability of an event
regardless of occurrence of other
events
µ
Occurrence of one event affects the
probability of occurrence of other
event
µ
Also known as marginal probability
µ
A conditional probability of an
occurrence is also called its likelihood
Eg.
µ
µ
LOS e
Eg.
P(heads) = 50%
P(head/rains) =50%
µ
µ
P(pass/study) = 80%
P(pass/studyc) = 50%
Multiplication, addition and total probability rules
Multiplication rule
e
Addition rule
Used to determine the probability
that at least one of two events
will occur
re
Used to determine the joint
probability of two events
Apply this rule when a
question says ‘and’
Apply this rule when a
question says ‘or’
P(AB) = P(A|B) × P(B)
P(A or B) = P(A) + P(B) − P(AB)
nT
P(A|B) = P(AB)
P(B)
Total probability rule -
Used to determine unconditional probability of an event,
given conditional probabilities
P(A) = P(A|B1) × P(B1) + P (A|B2) x P(B2) +....... P(A|Bn) × P(Bn)
Joint probability - Probability that all the events will occur at the same time
Fi
LOS f
For mutually exclusive events the joint probability is zero
For events that are not mutually exclusive, joint probability must be subtracted
from the total of unconditional probabilities to avoid double counting
Eg.
P(A) = 60%
P(B) = 30%
P(Both) = 60% × 30% = 18%
P(A)
P(B)
P(At least one) = 60% + 30% − 18% = 72%
P(None) = 1 − 72% = 28% Or
P(AB)
(1 − 60%) × (1 − 30%) = 28%
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LOS g
Dependent and independent events
Independent events
Dependent events
Ÿ
Occurrence of one event has no
influence on occurrence of other events
Ÿ
P (A|B) = P(A)
Ÿ
Getting 5 on a second roll of die is
independent of getting 5 on the first roll
of die
LOS h, i, j
1
Ÿ
Occurrence of one event is dependent
on occurrence of other events
Unconditional probability using total probability rule
Prob of good
economy and
rate increase
Interest rates
increase
Prob = 75%
Good economy next year
Interest rates
decrease
Prob of good
economy and
rate decrease
Prob = 25%
0.4 x 0.25 = 10%
re
e
Prob = 40%
Unconditional
probability
Conditional
probability
od)
P(Go
EPS = 10
0.4 × 0.6 × 10 = 2.4
40%
EPS = 8
0.4 × 0.4 × 8 = 1.28
70%
EPS = 6
0.6 × 0.7 × 6 = 2.52
%
Go
Fi
60%
= 40
Economy
P(
Joint
probability
Expected value
nT
2
0.4 x 0.75 = 30%
od c
)=
60
%
30
%
EPS = 3
0.6 x 0.3 x 3 = 0.54
Expected value of EPS = 2.4 + 1.28 + 2.52 + 0.54
= 6.74
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LOS k
Covariance and correlation
Correlation
Covariance
µ
It is a measure of how two assets move
together
µ
Covariance of return with itself is its
variance
µ
Expressed in terms of square units
µ
Population Cov(x,y) = ∑(X − X) (Y − Y)
n
µ
Sample Cov(x,y) = ∑(X − X) (Y − Y)
n−1
Cov(x,y) = r × σx × σy
µ
Range = −∞ to +∞
µ
Only +ve and −ve sign matters for
determining relationship b/w the variables
LOS l
Standardized measure of covariance
µ
Measures strength of linear relationship
between two random variables
µ
Does not have a unit
µ
r = Cov(x,y)
σx × σy
µ
Does not exhibit causal relationship
µ
Range = −1 to +1
µ
µ
µ
r = 1 means perfectly +ve relation
r = 0 means no correlation
r = −1 means perfectly −ve relation
e
µ
µ
Expected value, variance and standard deviation of portfolio
Expected value = W1E(R1) + W2E(R2) +W3E(R3) +.......+WnE(Rn)
re
1
Variance = (W1σ1)2 + (W2σ2)2 + 2W1σ1W2σ2 × r
(W1σ1)2 + (W2σ2)2 + 2W1W2 × Cov(x,y)
Standard deviation = √Variance
LOS n
When r = −1,
Sdp = (W1σ1) − (W2σ2)
Sdp = Lowest
When r = 0,
Sdp= √(W1σ1)2 + (W2σ2)2
nT
2
When r = 1,
Sdp = (W1σ1) + (W2σ2)
Sdp = Highest
Bayes’ formula
It is used to calculate updates probability
P(Ac|Bc) = 40%
P(A|B) = 30%
Fi
Eg.
P(B)
P(A)
P(B|Ac) = ?
B A = 9%
%
= 30
P(A c
) =7
P(
B )c
%
=30
P(B) = 30%
=
70
%
P(A)
P(
A )c
=
0%
B Ac = 21%
=60%
Bc A = 42%
40
%
Bc Ac = 28%
B Ac =
21
21+28
= 42.86%
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Counting problems
LOS o
Labeling
Permutation
n!
n1! x n2! x .... x nk!
n
Combination
n
Pr
Cr = nCn-r
Eg. A person has 8 cars. He uses 3 cars
for work, 3 other for long distance trips
and 2 other for commute other than
work. Calculate the no. of different
ways to label them.
Eg. How many different
ways are there to select
3 players from 5, if the
order of selection is
important ?
Eg. How many different
ways are there to select
3 players from 5, if the
order of selection is not
important ?
8!
3! x 3! x 2!
5 → 2nd(−) nPr → 3
5 → 2nd(+) nCr → 3 or 2 (5−3)
= 60
= 10
= 560
Permutation is used when order of selection is important
Fi
nT
re
e
Combination is used when order of selection is not important
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Common Probability Distribution
LOS a
Probability distribution - Describes the probabilities of all possible outcomes
of a random variable. Probabilities of all outcomes
should equal to 1
Discrete random variable - There is a finite number of possible outcomes. Eg.
number of stocks in portfolio
No. of stocks
100
200
300
% return
0.001 %
Continuous random variable
re
Discrete random variable
LOS b
e
Continuous random variable - There is an infinite number of possible outcomes. Eg.
Return earned in portfolio
Probability Function - P(X) = P(X=x)
X =1,2,3,4 P(X) = x else
10
nT
Eg.
P(X) = 0
The above function satisfies both the conditions of probability which are ;
a) 0 ≤ P(x) ≤ 1
LOS c
b) ∑ P(x) = 1
Discrete uniform
variable
Fi
Discrete non - uniform
variable
1
0
110
Number of people present in class
1
2
3
4
5
6
Probability distribution of a roll of a die
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Continuous non - uniform
variable
P(X) = 0, P(x) is between x1 and x2
LOS c & d
Continuous uniform
variable
Eg. Puncture on tyre. There are infinite
number of points on a tyre where
puncture can happen. Each point has
equal probability of occurance
Cumulative distribution function (cdf)
Eg.
X =1,2,3,4 P(X) = x
10
Cumulative
distribution function
P(1) = 1/10 = 10%
P(2) = 2/10 = 20%
P(3) = 3/10 = 30%
P(4) = 4/10 = 40%
F(1) = 10%
F(2) = 30%
F(3) = 60%
F(4) = 100%
F(-1) = 0.1587
re
e
Probability
density function
0.1587
LOS e & f
0
+1
nT
−1
Binomial random
variable
Fi
Outcome can be either
‘success’ or ‘failure’
When number of trials is 1,
it is called Bernoulli
random variable
Px x (1−P)n-x x nCr
P = Probability of success
n = No. of trials
X = No. of successes
−1
0
Eg.
P(win) = 70%, 4 matches, exactly 2 wins
Px x (1-P)n-x x nCr
(70%)2 x (1−0.7)4-2 x 4C2
= 26.46%
Ÿ Mean of binomial distribution = np
Ÿ Variance of binomial distribution = npq
Ÿ q=1−P
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LOS g
Binomial tree
Stock price (S) = 850 Uptick (u) = 1.2 Downtick (d) = 1/U = 1/1.2
1020 x 1.2
= 1224
Suu
1020 x 1/1.2
= 850
Sud
708 x 1.2 =
850
Sdu
708 x 1/1.2
= 590
Sdd
Su
850 x 1.2
= 1020
S
850
850 x 1/1.2
= 708
Sd
LOS h
Tracking error = Return on portfolio − Return on benchmark
LOS i
Continuous uniform distribution
Properties of continuous uniform distribution
e
ª For all a < x1 < x2 < b
(i.e. for all x1 and x2 between the boundaries a and b)
re
ª P(X < a or X > b) = 0
(i.e. probability of X outside the boundaries is zero)
ª P(x1 < X < x2) = (x2 - x1)/b - a
(This defines the probability of outcomes between x1 and x2)
ª Continuous uniform distribution will always have lower and upper bound (a,b)
ª Probability of X taking any value below ‘a’ or above ‘b’ will be zero
nT
Eg. X is uniformly distributed between 2 & 20. Calculate the probability that X will be between 6 & 15.
6
15
2
20
P(4<8) = 15 − 6
20 − 2
Fi
P(x) = 0 Because it is a continuous distribution
LOS j
è
è
è
è
è
è
è
Normal distribution
It is a continuous non-uniform distribution
Mean and variance needs to be defined
Skewness = 0
Kurtosis = 3
Mean = median = mode
A linear combination of a normally distributed random variable is also normally distributed
The probabilities of outcome further above and below mean get smaller and smaller but do
not go to zero (i.e. the tails get very thin but extend infinitely
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LOS k
Univeriate
distribution
Multiveriate
distribution
Single variable
More than one variables
A multivariate distribution with 10 variables has - 10 means 10 Variances 45 Correlations
n x (n-1) = 10 x 9 = 45
2
2
LOS l
Confidence interval
Eg.
X = 700 σ = 200
Calculate 90%, 95%, 99%
confidence interval
34% 34%
X ± (z-value)σ
13%
3%
90% - 700 ± (1.65)200
= 370-1030
3%
-2σ
-1σ
1σ
2σ
3σ
re
-3σ
e
13%
68%
95%
99%
95% - 700 ± (1.96)200
= 308-1092
99% - 700 ± (2.58)200
= 184-1216
LOS m
nT
Interpretation: We are 99% of the time
confident that the expected outcome will
lie between 184 and 1216
Standard normal distribution
Standard normal It is a normal distribution that is standardized so that its
distribution mean = 0 and standard deviation = 1
Fi
Z-value = Observation − Population mean
standard deviation
Z score =
Eg.
X = 400 σ = 200 μ = 700
400 − 700 = −1.5 At 1.5 Z-value, Probability = 93.32%
200
Therefore probability of value less
than 400 = 1 − 0.9332 = 6.68%
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LOS n
Shortfall risk and Safety first ratio
Shortfall risk
Safety first ratio
Probability that portfolio value
or return will fall below a
particular value or target over a
given period of time
Excess return per unit of risk
over minimum acceptable
return/threshold level.
SF ratio = Rp − Threshold return
Sdp
Higher the better
Lower the better
Eg.
Average return = 20%
SD = 3%
Threshold level = 15%
Z-value = 15 − 20 = −1.66
3
Shortfall
risk
Probability at −1.66 z-value = 95.15%
Therefore shortfall risk ;
1 − 0.9515 = 4.85%
LOS o
20%
= 1.66
e
15%
SF ratio = 20 - 15
3
nT
re
Normal and lognormal distribution
Normal distribution
Ÿ
Ÿ
No skew
Not bounded by zero
Lognormal distribution
Ÿ
Ÿ
Ÿ
Skewed to the right
Bounded by zero
Useful for modeling asset prices,
because they can not take
negative values
Fi
The logarithms of lognormally distributed random variables are normally distributred
LOS p
Discrete and continuous compounding
Discrete compounding - Annual, semi-annual, quarterly, monthly etc.
Continuous compounding - No. of compounding periods within a given time period
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Continuous compounding calculations
100
20%
0
117.35
100
0.8
0
100 x e0.2 x 0.8 = 117.35
LOS q
20%
ln 117.35
100
117.35
100
0.8
0
0.8 → 16%
20%
117.35
0.8
117.35 x e-0.2 x 0.8 = 100
1 → 20%
Monte Carlo simulation
Technique based on repeated generation of one or more risk factors that
affect security values, to generate a distribution
It is used to
Its limitations are
LOS r
It is complex
It is subject to model risk and input risk
Simulation is not an analytic method, but a
statistic one.
Ÿ Increased complexity does not necessarily
ensure accuracy
Ÿ
Ÿ
Ÿ
e
Value complex securities
Simulate profits/losses from a trading strategy
Calculate estimates of VaR to determine the
riskiness of a portfolio
Ÿ Simulate pension fund assets and liabilities to
examine the variability of the differences
between the two
Ÿ Value portfolios of assets that do not have
normal returns distribution
Ÿ
Ÿ
Ÿ
re
Historical simulation
It is based on actual change in value or actual change in risk factor for some prior period
Each iteration of simulation involves randomly selecting one of these past changes for
each risk factor and calculating the value of the asset or portfolio in question, based
on those changes in risk factor
nT
Its advantage is that it uses actual distribution of risk factors, which need not be estimated.
Fi
Its limitations are :
Past changes in risk factor may not be a good indication of future changes
It can not address the sort of ‘whatif’ questions that Monte Carlo simulation can
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LOS a
Simple random sampling and sampling distribution
1
2
Sampling and Estimation
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Simple random sampling
Systematic sampling
Method of selecting a sample in
such a way that each item in the
population has same likelihood
of being included in the sample.
Another way to form an
approximately random sample.
Eg. Drawing a sample of 5
apples from 50 to calculate
average weight.
Eg. Selecting every nth item
from the population
Sampling distribution - It is a probability distribution of all possible sample statistic
computed from samples drawn from the population
Sampling error = Sample statistic − Population parameter
re
LOS b
e
Sampling distribution does not have to be normal distribution
Mean, Variance,
Standard Deviation of
sample
Stratified random sampling - Uses a classification system to separate the
population into small groups, based on one
or more distinguishing characteristics. Each
subgroup is called as stratum.
nT
LOS c
Mean, Variance,
Standard Deviation of
population
Fi
Eg. Avg. calorie intake of a nation
Sample3
Sample4
Sample5
Results of these samples
are then pooled to form a
combined sample
N
W
C
E
Sample1
S
Sample2
It is often used in bond indexing because of the difficulty and cost of replicating entire
population of bonds.
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LOS d
Time-series and Cross-sectional data
Time-series data
Cross-sectional data
It consists of observations taken
over a period of time
It consists of observations taken
at a single point in time
Time-series and cross-sectional data can be pooled in the same data set.
Longitudinal data - Observations over time of multiple characteristics of the
same entity. Eg. Unemployment, GDP growth rates,
inflation of a country over 10 years.
Panel data - Observations over time of same characteristic of the
multiple entities. Eg. analysis of D/E ratio of 20
companies over 8 quarters.
Panel and longitudinal data are typically presented in table or spreadsheat form.
Central limit theorem
LOS e
ª
ª
Variance equals ‘σ2/n’ as sample size becomes large
If sample size n, is sufficiently large (n ≥ 30), the sampling distribution of the sample
means will be approximately normal
re
ª
e
ª Sample mean(x) approaches population mean(μ) as sample size becomes large
If central limit theorem works, population mean(μ) = mean of sampling distribution
Standard deviation of sampling distribution = σ/√n (standard error)
nT
ª
LOS f
Standard error of sample mean
Population variance unknown
σ
√n
s
√n
Fi
Population variance known
LOS g
Describe properties of an estimator
ª Unbiasedness - It is one for which the expected value of the estimator is equal to the
parameter you are trying to estimate
ª Efficiency - Unbiased estimator is also efficient if the variance of its sampling distribution
is smaller than other unbiased estimators of parameter you are trying to estimate
ª
Consistency - An estimator for which the accuracy of the parameter estimate increases as
the sample size increases
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LOS h
Point estimate and confidence interval estimate
Point estimate - It is a single sample value used to estimate population
parameter
Confidence interval It is a range of values in which population parameter is
estimate - expected to lie.
LOS i
Properties of t-distribution
Student’s t-distribution
It is a bell-shaped probability distribution
è
è
It is symmetrical about its mean
It is appropriate to use when n < 30,
population variance is unknown and
distribution is normal
LOS j
ª It is defined by degrees of freedom(DoF) (n − 1)
ª It has more probability in the tails (fat tails)
ª As DoF increase, t-distribution approaches
standard normal distribution (z-distribution)
ª t-distribution is flatter and has fatter tails than
normal distribution
ª As number of observations increase, distribution
becomes more peaked and tails become thin i.e.
it converges to z-distribution
Computation and interpretation of confidence interval
e
è
1
Significance level (α) = 1 − Confidence interval
re
90% confidence level = 10% significance level = 5% in each tail
Construction of confidence interval
2
nT
Point estimate ± (Reliability factor × Standard error)
3
Selection of test for
reliability factor
Fi
Population
variance is
known
Non -normal
distribution
Normal
distribution
Population
variance is
unknown
Non -normal
distribution
Normal
distribution
Z - distribution
t - distribution
n ≥ 30
n < 30
n ≥ 30
n < 30
Z - distribution
No
t/z distribution
No