3. Quantitative Methods Flashcards
Nominal scale
Names are discretionary
Ordinal scale
Scale order with specific criteria
e.g.: lower to higher
Interval Scale
Scale order based in ranges
0-10 % vol / 11-20 % vol / 21-30% vol
Ratio Scale
Scale order based in ratios
e.g.: debt-to-equity
2 x / 3x / 4x
Absolute Frequency
Example: #1 case (even if out of 20 or 30)
Relative Frequency
Example:
1 out of 10 = 10%
1 out of 20 = 5%
Histogram
Graphic based in two axis:
X: interval / specific values
Y: frequency
Population Average (formula)
Sum of Observations / #Number of Observations
Median
- Ordenate observations
- Choose the one that divides the # of observations in two
- If there are 4 observations, take the measure between numbers #2 and #3
Mode
The most frequent observation
- Distributions may be unimodal, bimodal, trimodal etc
Geometric Mean
1 + Rg = Raiz cúbica de (1+R1)(1+R2)(1+R3)
Harmonic Mean
- Calculate the average price of a stock, given:
- total budget waste
- average price for each tranche
- # number of tranches
Quantile
Quartile = divided by 4 Quintile = divided by 5 Decile = divided by 10 Percentile = divided by 100
Measure of Location
“What is the 3rd. quartile for the following distribution?”
Location where y% of the observations lie below, in a given distribution
L (y) = (n+1) * y / 100, where
Given:
Ascending order
y = Position below which y% of observations lie
Instructions:
- Count the numbers
- If L(y) = 8.5, interpolate 50% of the difference between observations #8 and #10
Mean Absolut Deviation (formula)
Average of all absolute deviations from the mean
- Pega todos os desvios
- Tira a média deles
Population Variance (formula)
Var = [(Deviation - Avg)^2 + (Deviation - Avg)^2] / 2
Standard Deviation (formula)
StDev = Raiz da Variância
Sample Variance (difference in comparison to Population Var)
Instead of using N, divide by (n-1)
Skewness
Measure of symmetry
Positive: outliers on the right; outliers on higher values
Negative: outliers on the left; outliers on lower values
Kurtosis
Kurtosis = 3 (for normal distribution)
↑ Kurtosis = ↑ Mode
Coefficient of Variation (formula)
CV = StDev x / Avg Value of X
CV = Vol / X (it should be the benchmark)
↑ CV = ↑ Risk
Order of Average, Mode, Median given skewness
Positive (+) Skewness: Avg > Median > Mode
Due to high outliers
Negative (-) Skewness: Mode > Median > Avg
Due to low outliers
- Median always in the middle
- Average is push to where outliers are (lower numbers / higher numbers)
Correlation range
Between (-1) and (1)
Variance range
Unbounded
Correlation (formula)
Correl = Cov(A,B) / StDevA * StDevB
Odds (concept)
Odds: 1 to 7 means one win to 7 loses.
Probability of wins: 1/8
Portfolio Variance (formula)
Var (Rp) = ∑ Wi r Wj Cov (Ri, Rj)
Var (Rp) = W1²Var(R1) + W2²Var(R2) + 2W1W2Cov(R1,R2)
Std Dev = Raiz disso