Lecture 8 - Expected value and variance criterion Flashcards
(94 cards)
What is the expected value (mean) of a random variable?
The expected value (mean) of a random variable is the average outcome you would expect if you repeated a random process many times.
How do different investments or time periods affect returns?
Investments in different assets or over different time periods can yield different returns, which are treated as outcomes of a random variable.
When should you use a simple average to calculate expected return?
Use a simple average when all investments are equally important or when all outcomes are equally likely.
What is the formula for calculating the simple average of returns?
What is a weighted average in the context of expected returns?
A weighted average is used when some investments are more important or likely than others. Different weights are assigned to each return, reflecting their importance or likelihood.
What is the formula for calculating the weighted average of returns?
Why would you use a weighted average instead of a simple average?
You use a weighted average when some outcomes are more likely or more important than others, to reflect the true expected value more accurately.
What does the sum of the weights pip_ipi equal in a weighted average?
What does variance measure in the context of a random variable?
Variance measures how much a random variable deviates from its mean, indicating how spread out the returns are from their average.
How is variance denoted mathematically?
What is the formula for sample variance?
Why do we use 1n−1\frac{1}{n-1}n−11 in the sample variance formula?
What is weighted variance and when is it used?
What is the standard deviation?
How is standard deviation interpreted in finance?
In finance, standard deviation is referred to as volatility and is used to measure the level of risk associated with investment returns. A higher standard deviation indicates more variability (risk) in returns.
What do the prices in the table represent?
The prices shown are adjusted prices (for shares) or index levels (for the FTSE 100), accounting for stock splits, dividends, and other corporate actions.
What is the formula to calculate the return from one period to the next?
How do you interpret the return calculated using the formula?
The return represents the percentage change in price from one year to the next, indicating the investment’s performance over that period.
What was the return for Tesco from April 1988 to April 1989?
What was the return for Tesco from April 1989 to April 1990?
Why are adjusted prices used in these calculations?
Adjusted prices are used because they account for stock splits, dividends, and other corporate actions, providing a more accurate reflection of the value.
What is the mean of the annual returns and how is it calculated?
What does the variance of returns measure?
Variance measures how much the returns deviate from the mean return, indicating the spread or volatility of the returns.
What is the formula for calculating variance?