Question 1

Which of the following options is the best description of regression?&#10;A) A mathematical equation describing the spread of values in a set of data&#10;B) A mathematical equation testing whether changing one variable affects another&#10;C) A mathematical equation describing the relationship between two variables&#10;D) A mathematical equation describing the skewness of values in a set of data

Accepted Answer

Regression is primarily used to describe the relationship between two variables, typically how one variable can predict or affect another.

Question 2

Which of the following options is an example of a non-causal relationship?&#10;A) Salesman height and average monthly sales&#10;B) Number of customers and revenue&#10;C) Daily temperature and number of ice-creams sold&#10;D) Income levels and average restaurant spend

Accepted Answer

Salesman height and average monthly sales is an example of a non-causal relationship because the height of a salesman does not cause or directly influence their average monthly sales. This relationship is likely coincidental or due to other factors not directly related to height.

Question 3

A regression line is given by the equation y = 720 - 0.35x. Estimate the value for y when x equals 400.&#10;A) 580&#10;B) 640&#10;C) 860&#10;D) 1020

Accepted Answer

To estimate the value for y when x equals 400, substitute x = 400 into the equation y = 720 - 0.35x: y = 720 - 0.35(400) = 720 - 140 = 580.

Question 4

A marketing officer wants to work out the relationship between the amount of money spent on social media and revenue increases. Which is the dependent variable in this case?&#10;A) Social media spend&#10;B) Revenue&#10;C) There is no clear dependent variable&#10;D) Both are dependent variables

Accepted Answer

The dependent variable is the outcome of interest, which in this case is the revenue increase. It is expected to depend on the amount of money spent on social media.

Question 5

A regression line is constructed using data where the independent variable has values ranging between 20 and 130. What term is used when estimating a value of y when x = 85?&#10;A) Extrapolation&#10;B) Estimation&#10;C) Interpolation&#10;D) Causation

Accepted Answer

Interpolation is the correct term because it refers to estimating a value within the range of the data points that were used to construct the regression line. Since 85 falls between 20 and 130, it is within the range of the independent variable values.

Question 6

What name is given to the regression line that allows a manager of a firm in Thailand to estimate the additional revenue generated for every additional 5,000 Thai Baht spent?&#10;A) Output regression line&#10;B) x on y regression line&#10;C) y on x regression line&#10;D) Input regression line

Accepted Answer

The correct term is "y on x regression line" because in this context, the additional revenue (y) is being estimated based on the additional expenditure (x, in this case, every additional 5,000 Thai Baht spent). This type of regression analysis helps in understanding how changes in the independent variable (x) affect the dependent variable (y).

Question 7

Which of the following options is the best explanation of why the least squares method of fitting a regression line is preferred?&#10;A) It is quick and easy&#10;B) It allows for individual interpretation&#10;C) It can be understood easily&#10;D) It is mathematically derived

Accepted Answer

The least squares method is preferred because it is mathematically derived, providing a systematic and reliable approach to fitting a regression line by minimizing the sum of the squares of the differences between observed and predicted values.

Question 8

A taxi-company owner in Kuala Lumpur has six cars of different ages. He records the annual cost of repairs (in Malaysian Ringgit). Using the data below, and the least squares method, work out the gradient (b) of the regression line (round to the nearest whole number).

A) 2659
B) 2682
C) 2696
D) 2702

Accepted Answer

The answer of A taxi-company owner in Kuala Lumpur has...

Question 9

Which of the following options is NOT a way in which a regression line can be fitted to a set of bivariate data?&#10;A) Inspection&#10;B) Reduced means&#10;C) Semi-averages&#10;D) Least squares

Accepted Answer

Reduced means is not a method used for fitting a regression line to bivariate data. The common methods include inspection, semi-averages, and least squares, with least squares being the most widely used due to its property of minimizing the sum of the squares of the differences between the observed and predicted values.

Question 10

Which of these statements about extrapolation is NOT true?&#10;A) The term is used to estimate a value for the dependent variable when the value used for the independent variable lies outside the observed range&#10;B) Extrapolation is commonly used to support forecasting or planning for future needs (for example raw materials as production increases)&#10;C) As extrapolation is taken from within the range of observed values we can be fairly confident of its accuracy&#10;D) Extrapolation must be undertaken with care, particularly when values get further from the observed range

Accepted Answer

Extrapolation involves estimating values outside the observed range, unlike interpolation which estimates within the observed range. Therefore, statement C, which suggests extrapolation is from within the observed range, is not true.

Deck 13: Regression Techniques