Quantitative Methods Flashcards
How would you describe a set of data that had outliers with large values?
Positive Skew
What does positive skew suggest about the mean, median and mode?
Mean > Median > Mode
How would you describe a set of data that had outliers with small/negative values?
Negative Skew
What does negative skew suggest about the mean, median and mode?
Mean < Median < Mode
What is the difference between a flat periodic rate of interest and the effective annual rate (EAR)?
Periodic rate: the quoted rate of interest for a year.
EAR: the actual rate of interest per year, once compounded.
EAR = ( 1 + periodic rate)m^ -1
m = no. of compounding intervals per year
What is primary data?
The collection of new data in relation to a specific project/task.
May be obtained via: scientific investigation, research, observation, discussion, questionnaires, market research etc.
What is secondary data?
Existing data that has already been collected by others. Tends to obtained at a relatively low cost.
What does population represent?
All the members of a specifically defined group e.g. the electorate, all UK companies etc.
What does a sample represent?
A subset of the full population that has been selected for investigation e.g. in establishing the CPI, the prices of sample items are investigated as opposed to all available goods.
What is raw data?
Data that is presented as a sample list of figures/values that may or may not be ordered.
When is tabulated data used?
When summarising large volumes of discrete data (data that can only take certain values, such as whole numbers).
When is grouped data used?
When summarising continuous data (data that can take any value within a range).
What is the formula for finding the arithmetic mean for raw data?
X = ΣX/n
What is the formula for finding the arithmetic mean for tabulated data?
X = ΣXf/n
What is the formula for finding the arithmetic mean for grouped data?
X = ΣXm/n
where m = midpoint of the range
What is the relationship between the arithmetic and geometric mean?
The arithmetic mean is always greater than or equal to the geometric mean.
What are the four measures of dispersion regarding the median?
Range
Deciles
IQR
Percentiles
What are the measures of dispersion regarding the arithmetic mean?
Standard Deviation
Variance
How do you calculate the IQR?
Q3 - Q1
What does the IQR exactly measure?
The range over the central most 50% of the population and is more representative (as extremes are excluded)
How do you calculate Q1 and Q3? (to find the IQR)
Q1: 1/4 (n + 1)
Q3: 3/4(n + 1)
What is a normal distribution?
A symmetrical distribution that is specifically defined by a mean (expected return) and standard deviation (measure of risk).
- Total area under the distribution = 1
- Central values more likely than extreme values.
- Distribution has a single σ.
Under normal distribution, what statistics are always the case which can be used for analysis of risk and return?
1 σ from mean = 68.26% of values
1.96 σ from mean = 95% of values
3 σ from mean = 99% of values
On what axis does the dependent variable go?
Y-axis
On what axis does the independent variable go?
X-axis
What is a correlation coefficient (r)?
A relative measure indicating how two variables move with respect to each other. It measures the direction and degree of linear association between two variables.
It will have any value between + 1 and - 1.
The meaning of the correlation coefficient can be best understood by considering the means.
What value does a perfect positive correlation have?
+ 1
What value does a non-perfect positive correlation have?
0 < r < 1
What value does a perfect negative correlation have?
- 1
What value does an uncorrelated coefficient have?
0