Quantitative Methods Flashcards
What is “frequency?”
The number of times something appears
What is “relative frequency?”
The number of times something appears as a percentage of the total observations.
What does the Sharpe ratio represent?
The excess return earned per unit of risk taken
What does standard deviation represent?
Standard Deviation is the measure of dispersion away from the mean of a data set.
Name the steps in calculating variance.
- Take the differences of each data point from the mean.
- Square the differences
- sum the squared differences.
- Divide the sum of squares by the number of data points.
How do you convert variance to standard deviation?
Take the square root
What is the conceptual difference between variance and standard deviation
They are the same however, standard deviation is in the same units as the mean, whereas variance is in squared units.
If fund A’s coefficient of variation is lower than fund B, which fund has inherently more risk, all things being equal?
Fund A
What is the formula for a combination binomial
n!/r!(n-r)!
When would you use a combination binomial?
When determining the number of possible outcomes.
What are the four types of scales and describe them.
Nominal - Categorize or count data but do not rank them.
Ordinal scales- sort data into categories and then are ranked but do not tell us anything about the differences between the categories
Interval scales - rank observations and describe the diferences in between observations but does not have a true zero point. For example the difference between two temperatures.
Ratio scales - interval and have a true zero. I.E. Dividends paid.
Name three characteristics of the geometric mean
- The geometric mean is always less than, or equal to the arithmetic mean
- The geometric mean equals the arithmetic mean only when all observations are equal.
- The difference between the geometric and arithmetic mean increases as the dispersion in observed values increases.
What is the Harmonic Mean?
Much like the weighted mean where the weight of an observation is inversely proportional to its magnitude.
It will always bea less than the geometric mean and therefore the rithmetic mean.
What is the mean absolute deviation?
The average of the absolute differences from the mean.
What is Chebyshev’s Inequality? What is the equation?
It shows the % observation within k standard deviations from the mean. It is calculated as: 1 - 1/k^2
Explain the Coefficient of Variation, how its calculated and why it is usefull.
It represents a ratio of the standard deviation to its mean. It illustrates a meaningful ratio for datasets with varying observations. CV = s/mean
Explain Kurtosis and and the different classifications of Kurtosis.
Kurtosis measures the extent to which a distribution is more or less peaked than a normal distribution. Normal distributions will have a Kurtosis of 3.
A distribution that is more peaked and has fatter tails than a normal distribution and has a Kurtosis of greater than three is called leptokurtic.
Platykurtic is less peaked and has thinner tails than a nomral distribution, and has a kurtosis less than zero.
Mesokurtic is identical to a normal distribution and has n excess kurtosis of zero.
What is an outcome?
the observed value of a random variable
What is an event?
a single outcome or set of outcomes.
Explain the difference between empirical, subjective, and a priori probability.
Empirical estimates the probability of an event based on its frequency of occurrence in the past. A subjective probability draws on subjective reasoning and personal judgement. Priori is based on formal analysis and reasoning.
Give the formulas for odds for and odds against
F= a/(a+b) A=b/(a+b)
What does the Dutch Book Theorem state?
The Dutch Book Theorem states that if the probabilities reflected in the stock prices are not consistent, they give risk to profit opportunities. As investors take positions to take advantage of such opportunities, the inconsistency is eventually eliminated.
What is the formula for conditional probability?
P(A|B)=P(AB)/P(B)