Commerce MCQs
Topic Notes: Commerce
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
91
Evaluate the following statements regarding statistical correlation and regression: 1. Rank correlation and Karl Pearson's coefficient share the same range. 2. Correlation is independent of origin but not scale. 3. Covariance between X and Y is defined as Σxy/n. 4. bxy represents the regression coefficient of X on Y. 5. If bxy=0.4 and byx=1.6, the coefficient of determination is 0.8.
Answer:
1, 3 and 4
Statement 1 is true as both range from -1 to +1. Statement 3 is the standard definition of covariance. Statement 4 correctly identifies bxy as the regression coefficient of X on Y. Statement 2 is false because correlation is independent of both origin and scale. Statement 5 is false because the coefficient of determination (r squared) is the product of the two regression coefficients (0.4 * 1.6 = 0.64), not 0.8.
92
Which of the following statements regarding regression coefficients is true?
Answer:
greater than one
It is a property of regression coefficients (bxy and byx) that both cannot be greater than one simultaneously. If one coefficient is greater than one, the other must be less than one, because their geometric mean is equal to the correlation coefficient, which cannot exceed one.
93
In regression analysis, what term describes the mathematical equation relating the response variable (y) to the explanatory variable (x)?
Answer:
the regression model
A regression model is a statistical tool used to estimate the relationship between a dependent variable (response variable) and one or more independent variables (explanatory variables). It allows researchers to predict the value of the response variable based on the values of the explanatory variables.
94
Regression analysis is primarily used as a measure of which of the following?
Answer:
Cause and effect relationship
Regression analysis is designed to model the relationship between a dependent variable and one or more independent variables. It helps in understanding how the typical value of the dependent variable changes when any one of the independent variables is varied, effectively allowing researchers to infer cause-and-effect relationships, unlike correlation which only measures the strength of association.
95
Which statistical method is utilized to determine the average change in a dependent variable resulting from a one-unit change in an independent variable?
Answer:
regression method
Regression analysis is a powerful statistical technique used to estimate the relationships between variables. It specifically measures how the dependent variable changes when one of the independent variables is varied, while holding other independent variables fixed. This method is fundamental in predictive modeling and cost estimation, allowing analysts to quantify the impact of specific drivers on total costs or other outcomes.
96
In regression analysis, what term describes the predicted rate of change in the dependent variable resulting from a unit change in the independent variable?
Answer:
Slope
The slope coefficient in a simple linear regression equation represents the change in the dependent variable (Y) for every one-unit increase in the independent variable (X). It indicates the direction and magnitude of the relationship between the variables.
97
Calculate the coefficient of determination given an unexplained variation of 350,050 and a total variation of 700,505.
Answer:
0.5003
The coefficient of determination (R-squared) is calculated as 1 minus the ratio of unexplained variation to total variation. Here, 1 - (350,050 / 700,505) equals approximately 1 - 0.4997, which is 0.5003. This metric represents the proportion of the variance in the dependent variable that is predictable from the independent variable.
98
What specifically does the correlation coefficient measure?
Answer:
Linear relationship between two variables
The Pearson correlation coefficient (r) is a statistical measure that quantifies the strength and direction of the linear relationship between two continuous variables. It ranges from -1 to +1, where values closer to these extremes indicate a stronger linear association.
99
In regression assumption testing, what is the term for the condition where the variance of the error terms is constant?
Answer:
homoscedasticity
Homoscedasticity refers to the assumption in linear regression that the variance of the error terms (residuals) is constant across all levels of the independent variables. If the variance is not constant, the condition is known as heteroscedasticity. Maintaining homoscedasticity is crucial for the validity of standard errors and hypothesis tests in regression analysis.
100
Which statistical measure indicates the proportion of variance in the dependent variable (y) that is explained by changes in the independent variable (x)?
Answer:
Coefficient of determination
The coefficient of determination, denoted as R-squared, measures the proportion of the variance in the dependent variable that is predictable from the independent variable. It is a key metric in regression analysis.