Time Value of Money
ordinary annuity END
annuity due BGN


- Perpetuity
- payment for infinite time period
- where PV = Present Value of the Perpetuity, A = the Amount of the periodic payment, and r = yield , discount rate or interest rate.


Discounted Cash Flow
- Holding Period Return
- true yield
- (ending value + dividend)/beginning value - 1

- Bank discount yield
- percent discount form face value

- Effective annual yield
- for n compounding periods per year:

-
- for infinite time period:

Statistical Concepts



- measurement scales(NOIR) - Nominal(no context; weakest), Ordinal(accoding to characteristics), Interval(special meaning to difference to numberical values), Ratio(scale amounts; strongest)
- Correlation: degree of linear dependence between the variables
- 1 in the case of an increasing linear relationship,
- ?1 in the case of a decreasing linear relationship,
- some value in between in all other cases
- the closer the coefficient is to either ?1 or 1, the stronger the correlation between the variables.


- Permutation: order matters nPr = n! / (n-r)!
- Combination: order does not matter nCr = n! / r! (n-r)!


- Chebyshev’s inequality : no more than 1/k2 of the values are more than k standard deviations away from the mean.

- Sharpe ratio: measure of the excess return (or Risk Premium) per unit of risk in an investment asset

- Roy's Safety-First criterion
P(Ra < Rm) = [E(RP)-RL]/σP
- Skewness
- measure of the asymmetry
- Positive skew: mode < median < mean
- negative skew: mode > median > mean

- Kurtosis
- measure of the "peakedness"; can be either leptokurtic or platykurtic
Probability Concepts
- Probability distribution: of all possible outcomes for a random variable
- discrete distribution: finite number of possible outcomes
- continuous distribution: infinite number of possible outcomes
- Probability function p(x): probability that a discrete random variable will take on the value x
- Probability density function f(x): probability a continuous random variable will take on a value within a range
- Cumulative distribution function F(x): probability a random variable will be less than or equal to a given value
- Binomial random variable: probability of exactly x successes in n trials
- Confidence interval: a range of values around an expected outcome within which we expect the actual outcome to occur some specified percent of the time
- 90% confidence interval = Χ ± 1.65σ
- 95% confidence interval = Χ ± 1.95σ
- 99% confidence interval = Χ ± 2.58σ
- Degrees of freedom
- sufficiently high df is approximately normal
- higher degrees of freedom, thiner tails
- Standard normal distribution: μ=0 σ=1
where
plug-in z-value to get F(z) from z-table

CV = σ / μ
- Monte Carlo Simulation: to estimate distribution of derivatives prices or of Net Present Values
- Continuous compounding = ln(1+HPR)
Sampling and Estimation
- Sampling: to make inferences about the parameters of a population
- time-series data- gathered from each time periods
- cross-sectional data- data from a single time period
- Stratified sampling: random picks within subgroups
- Central limit theorem
- sample mean for large sample sizes will be distributed normally
- as sample size increases, becomes more accurate in respect to population data
- holds for n > 30
- Test statistic: difference between population sample and hypothesized value


- Student's t-test
- used when sample size is small or variance unknown

used when H0: σ² = σ0<super>2</super>
- Confidence interval (level of significance:probability of rejecting true H0)
- 68% of observations fall in ±1σ
- 95% of observations fall in ±1.96σ
- 99% of observations fall in ±3σ
- Types of Bias
- data-mining~ : repeatedly doing tests on same data sample
- sample selection~ : sample not really random
- survivorship~ : sampling only surviving firms
- look-ahead~ : using information not available at the time to construct sample
- time-period~ : relationship exists only during the time period of sample data
Hypothesis Testing
- H0: hypothesis set up to be nullified or refuted in order to support an alternate hypothesis.
- H1: alternative hypothesis
- Type I error(Significance level): rejecting a null hypothesis when it is actually true; decreases as confidence interval(tradeoff) increases
- Type II error(1 - Power of test): failing to reject a null hypothesis when the alternative hypothesis is the true; increases as confidence interval increases
- Volatility estimation
- unbiased~ : has an expected value equal to the true value of the population parameter
- consistent~ : more accurate the greater the sample size
- efficient~ : has the sampling distribution that is less than that of any other unbiased estimator
- Statistical significance omits transaction costs, taxes, risk factor from economical significance
Technical Analysis
- Assumptions
- stock values determined by supply & demand
- S&D driven by both rational & irrational behavior
- security prices move in trends
- changes observed in market price behavior
- Fundamental analysts -> look for changes in stock values; stock prices adjust quickly to new information
- Technical analysts -> look directly for signals & indicators of changes in S&D; stock prices move in trends that can persist for long periods
- + quick&easy, psychological reasons
- - subjective judgement required for interpretation, no evidence in price trends, value neutralized
- Technical indicators
- Contrarian~ : do opposite of what majority are doing
- Smart money~ : mimic investors known for investment success
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