Quantitative Methods Flashcards
Quantitative Methods
Interest Rates
Three ways to interpret interest rates
- Required rate of return
- Discount rate
- Opportunity cost
Quantitative Methods
Interest Rates
3 components of interest rates
- Risk free rate
- Inflation
- Default risk
Quantitative Methods
Interest Rates
Periodic interest rate
Simple rate of interest over a single compounding period
e.g. interest rate of 1.5% per quarter
Quantitative Methods
Interest Rates
Stated annual interest rate
= quoted interest rate
Annual rate ignoring compounding e.g. 4 * quarterly interest rate
Quantitative Methods
Interest Rates
Effective annual rate (EAR)
Annual interest rate taking into account compounding
Quantitative Methods
What is an “annuity due”?
Annuity with first payment at T0 (so last payment at T(n-1)
Formula: FV of annuity
IRR Problems
1 - Reinvestment Problem
2 - Scale Problem
3 - Timing Problem
IRR Problem 1
Reinvestment Problem
Assumes that all cash flows can be reinvested immediately at the IRR rate.
IRR Problem
2 Scale Problem
IRR ignores the scale of the return unlike NPV which would prioritise larger cash returns with the same IRR.
IRR Problem 3
Timing Problem
In the case where two projects have differing cash flow profiles (big cash flows early or late) IRR comparison is not useful.
Definition: Holding Period Return (HPR)
aka Total Return
This is the total return over a given period, including capital and distributions.
Dollar Weighted Rate of Return
Basically the IRR of an investment, taking amount and timing of cash flows into account.
So investing more cash when portfolio value is low leads to positive return, even if portfolio performance over the whole period is unchanged.
Thus a measure of what you earned from investing in the portfolio over the period, not a measure of the performance of the portfolio itself.
Time Weighted Rate of Return
The compound growth rate of $1 invested in the portfolio over the period. Ignores timing of cash flows (ie purchase/sale of portfolio) so is appropriate for measuring portfolio performance.
Simply calculate the return for each period (divs and share price movement) and then annualise.
Money Market Instruments
Bank Discount Yield
Definition and formula
This is the basis on which money market instruments are quoted.
Discount = FV - price you pay
t = Time to maturity
Money Market Instruments
4 money market interest rates
- Holding Period Yield (HPY): simple periodic rate, just discount/FV or (FV-PV)/PV
- Bank Discount Yield: Odd simple annualised rate used for money market, (discount/FV) * (360/t)
- Money Market yield (rm): Simple annualised yield, 360 basis, =HPY * 360 / t
- Effective Annual Yield: Proper compound annual yield, = (1+HPY)365/t - 1
Money Market Instruments
Bank Discount Yield
Issues with them
- Based on the FV instead of purchase price, return should be measured off purchase price
- Annualised of 360 days instead of 365
- Annualised with simple interest, ignores value of compounding
Money Market Instruments
Holding Period Yield
Total return earned if held to maturity (not annualised).
Money Market Instruments
Effective Annual Yield
The annualised HPY based on 365 day year, annualised.
Money Market Instruments
Money Market Yield
aka?
definition
calculation from BDY
a.k.a. CD equivalent yield
Annualised HPY using simple interest on 360 day basis. (HPY = holding period yield).
rmm = HPY * 360 / t
From BDY:
Bonds
Bond Equivalent Yield
Bond yields (in the US) typically quoted semi-annually. This method just doubles it (ignoring compound interest) to get an annualised yield.
So DON’T compare an annual yield bond to the BEY of a semi-annual yield bond.
Statistics
Definition of Parameter
A characteristic (value) of a population (not of a sample), denoted by greek letter.
For example the mean.
In investments, examples inlcude mean return and standard deviation of returns.
Statistics
Definition of a Statistic
An estimate of a parameter of a population, taken from a sample of that population.
Statistics
Definition of Inferential Statistics methods
Required qualities of the sample
Inferential Statistical Methods are used to draw conclusions about a large group based on a sample taken.
Require the sample to be either random or representative in different cases.
Statistics
Measurement
Definition of Nominal Scale
Assigning items to groups or categories, such as race or sex, qualitative rather than quantitative.
No ordering or ranking implied, but can allocate numbers to the groups (eg, 1 - value funds, 2 - growth funds).
Statistics
Measurement
Definition of Ordinal Scale
Allocated to each item a ranking for a certain characteristic (eg scale of 1 to 10 between worst and best performing manager).
There is an ordering implied but the scale is arbitrary and distances between the ranks not necessarily consistent.
Statistics
Measurement
Definition of Interval Scale
Items in population given a ranking for a certain characteristic, where an order is implied and the distance between each rank is standardised. Such that the difference between 0 and 10 is the same as 20 to 30.
However no zero point is defined therefore doubling from 10 to 20 is not the same as doubling from 20 to 40.
Statistics
Measurement
Definition of Ratio Scale
Ranking of items within a population on a given parameter, which has an ordering, where difference between each ranking is standardised and there is a defined zero point. So the effect of doubling from 10 to 20 is the same as from 20 to 40.
e.g. temperature on the Kelvin scale (NOT farenheit since the zero point in farenheit is arbitrary)
Statistics
Measurement
Order of Strength of the Scales
N - Nominal
O - Ordinal
I - Interval
R - Ratio
Statistics
Frequency Distributions
Definition of Absolute Frequency
Number of actual observations in a given interval.
Statistics
Frequency Distributions
Definition of Relative Frequency
The result from dividing the absolute frequency of a return interval by the total number of observations.
Statistics
Frequency Distributions
Definition of Cumulative Absolute Frequency
and
Cumulative Relative Frequency
Result of cumulating the results form absolute and relative frequency as you move from one interval to the next.
Statistics
Measures of Central Tendency
Definition of Geometric Mean
3 characteristics
See formula.
- Used when calculating returns over multiple periods
- Exists only if all values are greater than zero
- Always less than arithmetic mean unless numbers are all the same (in which case they’re the same)
Statistics
Measures of Central Tendency
Definition of Harmonic Mean
Special cases with 2 or 3 numbers
Special cases also given:
H(x1,x2) = 2x1x2 / (x1 + x2)
H(x1,x2,x3) = 3x1x2x3 / (x1x2 + x2x3 + x1x3)
Statistics
Median - ‘iles
Examples
Inter-quartile range
- There are 3 quartiles, 4 quintiles, 9 deciles and 99 percentiles in a data set
- They split the population into 4, 5, 10 and 100 groups
- Q1 is the first or lowest quartile, Q3 the highest
- Distance from Q1 to Q3 is the inter-quartile range
Statistics
Deviation
Range
Difference between the lowest and higest values in a population of numbers.
Statistics
Deviation
Mean Absolute Deviation
Take the absolute difference between each value and the mean, then take the average of those results.
Statistics
Deviation
Variance (for a population)
This is the average squared deviation of each value from the mean.
Statistics
Deviation
Variance (for a sample)
Same as population, average of squares of difference between values and the sample mean.
Dividing by n results in a baised estimator of population variance, using n - 1 gives an unbaised estimator.
Statistics
Deviation
Standard Deviation
1sd and 2sd bands
Simply the square root of the variance.
Normal distn - 68% within 1 sd, 95% within 2 sd.
Standard Deviation not directly comparable between different data sets since means are different sizes (not a relative measure).
Statistics
Deviation
Coefficient of Variation
A relative dispersion measure, so allows comparison between different data sets.
Simply divide standard deviation by the mean.
a.k.a. Relative Standard Deviation
Statistics
Chebyshev’s Theorem
For any sample/population, the proportion of observations within c standard deviations of the mean is at least 1 - 1/c2.
Works on sample and population, discrete or continuous data.
Allows us to measure minimum amount of dispersion from the standard deviation.
Statistics
Sharpe Measure
rp = mean return of portfolio
rf = risk free mean return
σp = standard deviation of portfolio
a.k.a. reward to variability ratio
Measures the reward to volatility trade-off and recognises the existence of a risk-free return.
Statistics
Skewness
Definition
Value for normal distn
The degree of asymmetry of a data set.
Normal distribution has zero skewness.
Positively Skewed Distribution means a long tail to the right (a few big wins, lots of small losses). Also say skewed to the right.
Statistics
Skewness
Where are mean, median and mode when skew is positive?
Mode: The peak of the distribution.
Mean: Pulled towards the long tail (extreme values).
Median: In-between.
Statistics
Skewness
Formula
Conditions for calculation to be valid
Valid when N is large.
Zero for normal distribution.
Statistics
Kurtosis
Definition
Measure of how much a distribution is stretched out to the tails or peaked around the mean, regardless of skew.
Normal distribution has a neutral kurtosis.
Statistics
Kurtosis
Words for types of kurtosis
- Platykurtic: Low peak, more returns with large deviations from the mean.
- Leptokurtic: Tall peak, few returns with large deviations from the mean.
- Mesokurtic: Same kurtosis as normal distribution.
Statistics
Kurtosis
Formula
Formula is for excess kurtosis.
Normal distribution has kurtosis of 3 and excess kurtosis of 0.
Probability
Empirical Probability
A probability based on frequency of occurence in a set of historical data.
Probability
Priori Probability
A probability based on logical analysis rather than historical observation (eg 50% chance of heads on coin toss).