Statistics Flashcards
Which of the following correctly describes the formula for a line of best fit?
A y=bx
B y=(a+b)x
C y=a+bx
D y = a+b+x
C - y=a+bx
y is the dependent variable and x is the independent variable.
If 10% of the workforce earn £30,000 or less, 13% earn between £30,000 and £40,000, 42% earn between £40,000 and £50,000, 25% earn between £50,000 and £60,000, and 10% earn in excess of £60,000, what is the cumulative percentage earning less than £50,000?
A 35%
B 90%
C 10%
D 65%
D - 65%
Cumulative percentage earning less than £50,000 is 10% + 13% + 42% = 65%.
Andy Nyman, a research analyst, collects monthly share price data for a company. How can this data be best categorised?
A Cross-sectional
B Continuous
C Discrete
D Categorical
B - Continuous
Share prices are continuous data, limited only in the equipment used to measure (or report) the data.
The best way to compare two variables is to use:
A A scatter diagram (scattergram)
B A histogram
C A pie chart
D A cumulative frequency graph
A - A scatter diagram (scattergram)
A scatter diagram plots one variable against another in order to determine whether there is any relationship between the two. The independent variable is always plotted on the x-axis.
The sample standard deviation of a series is:
A The square of the sample variance
B The sample variance divided by the number of values in the series
C The sample variance divided by the number of values in the series minus one
D The square root of the sample variance
D - The square root of the sample variance
Which of the following is true of scattergrams?
A They are used to represent the rate of change over time
B The vertical axis is the dependent variable
C The horizontal axis is the dependent variable
D The area under a scattergram represents the frequency
B - The vertical axis is the dependent variable
Scattergrams show the relationship between variables.
A commodity has annual inflation rates for the last five years as follows:
5% 11% -3% -9% 22%
What is the average rate of inflation?
4.65
The ‘average rate’ means the geometric mean.
First, multiply the rates together: 1.05 x 1.11 x 0.97 x 0.91 x 1.22 = 1.25512 Take the fifth root of this number: = 1.0465 Lastly subtract the 1: = 0.0465 or 4.65%.
Calculate the mean and median of the following returns on 11 shares:
-1.2, 2.8, 3.1, 4.1, 4.3, 4.4, 4.5, 6.7, 6.7, 5.2, 12.2
A Mean = 4.4, median = 4.8
B Mean = 4, median = 4.4
C Mean = 4.8, median = 4.4
D Mean = 4.8, median = 6.7
C - Mean = 4.8, median = 4.4
The mean is the sum of all the returns divided by the number of yields:
(-1.2 + 2.8 + 3.1 + 4.1 + 4.3 + 4.4 + 4.5 + 6.7 + 6.7 + 5.2 + 12.2 ) / 11
= 4.8
The median is the central value after putting them all in numerical order:
-1.2 2.8 3.1 4.1 4.3 4.4 4.5 5.2 6.7 6.7 12.2
i.e. 4.4.
In a positively skewed distribution:
A The mode will be less than the median and mean
B The mean and median are equal, but less than the mode
C The mean and mode are equal, but greater than the median
D Mean, mode and median are equal
A - The mode will be less than the median and mean
A positively skewed distribution is not symmetrical. Its peak is to the left of the spread of data, and it has a gently sloping tail to the right. The peak represents the mode, the median comes next (the central value), and above this is the mean.
Which of the following is not true of bivariate linear regression?
A x is the independent axis
B a is the intersect with the x axis
C b is the coefficient of the gradient
D y is the dependent variable
B - a is the intersect with the x axis
The inter-quartile range is:
A A measure of distribution dominated by extreme values
B A measure of distribution not dominated by extreme values
C The variance of the range
D A measure of central tendency
B - A measure of distribution not dominated by extreme values
The inter-quartile range includes only the SECOND and THIRD quartiles and is therefore not dominated by extreme values.
Jane, an analyst, wants to present what percentage of a particular gilt issue is held by each category of investor, such as hedge funds, insurance companies, etc.
Which of the following would best represent this information?
A Scattergram
B Histogram
C Tubularogram
D Pie Chart
D - Pie Chart
A pie chart shows relative percentages and is ideal for situations where the total adds up to 100%, such as the asset allocation of a portfolio, or the example in the question.
Given the following information regarding employees’ salaries:
Salary (£,000s) - Number of employees
Less than 30 - 15
31 to 40 - 25
41 to 50 - 35
51 to 60 - 15
61 or above - 10
What is the cumulative percentage of employees with an annual salary less than or equal to £50,000?
A 25%
B 35%
C 75%
D 80%
C - 75%
The total number of employees is 100. The total number of employees with a salary below £50,000 is 15 + 25 + 35 = 75. The cumulative percentage is therefore 75 / 100 = 0.75 or 75%.
An analyst wishes to plot a graph showing rates of change of share prices over time. Which of the following graphs would be the most appropriate?
A Scatter diagram
B Lorenz curve
C Pie chart
D Semi-log graph
D - Semi-log graph
Semi-log graphs (or log graphs) illustrate the RATE OF CHANGE over time.
Calculate the median of the following returns achieved by seven fund managers:
2.0% 3.2% 5.0% 6.6% 2.0% 3.3% 6.2%
A 2.0
B 3.3%
C 6.6%
D There is no median
B - 3.3%
The median is the value of the central number in an array of data. First put the data in numerical order (an array), and then find the item in the centre:
2.0 2.0 3.2 3.3(median) 5.0 6.2 6.6
NB: 2.0 is the mode