Numerical Descriptive Measures Flashcards
When is the mean usually greater than the median?
When there is a negative skewe
What is another name for the 50th percentile?
The median
What can you tell about the rest of the variables if yours is the 75th percentile?
That 75% of the other variables are lower than yours and the 25% of the other variables are higher than yours 
What is the five number summary of a date set
Is the smallest variable, the largest variable in the quartiles in between
What is the range of human age?
125-0=125
Why is range not a good measure of dispersion?
Because it only measures extremes
What is the difference between mad and the variance?
Measure of absolute deviation takes the absolute off the value minus the average while the variance is the same but squared instead of for the absolute value. Also, variance subtracts one when dividing the sum
What is the coefficient of variation?
It is the standard deviation divided by the mean, and its gives a ratio of how much variables vary
What is mean variance analysis?
The mean of an assets is its reward, and the variance is the risk associated
What does a high sharp ratio tell us about an asset?
But it’s either low risk or high reward compared to a risk-free asset
What is excess return?
The rewards investors get for the risk they take. This is the result of the sharp ratio
What does chebyshevs theorem show us?
The minimum amount of observations that falls within K standard deviations
Does chebyshevs theorem rely on the shape of the distribution
Apparently not, it can be asymmetrical or anything… no there must be a misunderstanding if there are two chunks way apart
What does the Z score measure?
The distance of an observation from the mean, in terms of standard deviations
When might covariance yield inaccurate results?
When the relationship between the two variables or is nonlinear
