Reading 7: Introduction to Linear Regression
50 questions available
Key Points
- Dependent variable (Y) is explained; Independent variable (X) is the predictor.
- OLS minimizes the sum of squared vertical distances (residuals) between observed and predicted Y values.
- Slope (b1) = Cov(X,Y) / Var(X).
- Intercept (b0) = Mean(Y) - b1 * Mean(X).
- Assumptions: Linearity, Homoskedasticity, Independence, Normality.
Key Points
- SST = RSS + SSE.
- R-squared = RSS / SST; measures explained variation.
- SEE = square root of (SSE / (n - 2)).
- F-statistic = MSR / MSE; tests if the model explains significant variation.
- t-test determines if the slope is statistically significant.
Key Points
- Predicted Y is calculated using estimated b0 and b1 with a given X.
- Prediction intervals depend on the standard error of the forecast.
- Log-lin model: Slope represents percentage change in Y for unit change in X.
- Lin-log model: Slope represents unit change in Y for percentage change in X.
- Log-log model: Slope represents percentage change in Y for percentage change in X (elasticity).
Questions
In a simple linear regression model, the variable that serves as the predictor is best described as the:
View answer and explanationWhich of the following best describes the method of Ordinary Least Squares (OLS)?
View answer and explanationIf the covariance between variables X and Y is 20 and the variance of X is 10, what is the estimated slope coefficient for the regression of Y on X?
View answer and explanationGiven a regression equation Y = 0.5 + 1.2X, how is the slope coefficient interpreted?
View answer and explanationCalculate the intercept of a regression line where the mean of Y is 15, the mean of X is 5, and the estimated slope coefficient is 2.
View answer and explanationWhich of the following is NOT a necessary assumption of simple linear regression?
View answer and explanationThe condition where the variance of the error term is not constant across all observations is known as:
View answer and explanationIn the context of regression analysis, the term 'residuals' refers to:
View answer and explanationIf the Regression Sum of Squares (RSS) is 60 and the Sum of Squared Errors (SSE) is 40, what is the Total Sum of Squares (SST)?
View answer and explanationThe coefficient of determination (R-squared) measures:
View answer and explanationIf a regression model has an RSS of 45 and an SST of 100, what is the value of R-squared?
View answer and explanationThe Standard Error of Estimate (SEE) is calculated as the square root of which value?
View answer and explanationIn a simple linear regression with 32 observations, what are the degrees of freedom for the error term?
View answer and explanationCalculate the F-statistic if the Mean Regression Sum of Squares (MSR) is 100 and the Mean Squared Error (MSE) is 20.
View answer and explanationIn a simple linear regression, the F-test is equivalent to determining the statistical significance of:
View answer and explanationThe appropriate degrees of freedom for the numerator in the F-test for a simple linear regression is:
View answer and explanationIf the calculated t-statistic for a slope coefficient is 2.5 and the critical t-value is 2.0, what is the appropriate conclusion?
View answer and explanationFor a simple linear regression, the null hypothesis used to test the statistical significance of the slope coefficient is:
View answer and explanationIf the standard error of the slope coefficient is 0.5 and the estimated slope is 1.5, what is the calculated t-statistic for testing if the slope is zero?
View answer and explanationGiven a regression equation Y = 2 + 3X, what is the predicted value of Y when X is 4?
View answer and explanationIn a log-lin model where ln(Y) = b0 + b1*X, how is the slope coefficient (b1) interpreted?
View answer and explanationIn a lin-log model where Y = b0 + b1*ln(X), the slope coefficient indicates:
View answer and explanationWhich functional form involves taking the natural logarithm of both the dependent and independent variables?
View answer and explanationIf a stock's return is explained by the market return, the stock's return is the:
View answer and explanationIf the correlation coefficient between two variables is 0.7, what is the coefficient of determination (R-squared)?
View answer and explanationWhat is the relationship between Total Sum of Squares (SST), Regression Sum of Squares (RSS), and Sum of Squared Errors (SSE)?
View answer and explanationIn an ANOVA table, the Mean Squared Error (MSE) is calculated by dividing:
View answer and explanationA residual plot that shows residuals increasing in magnitude as the independent variable increases indicates:
View answer and explanationIf the confidence interval for a slope coefficient includes zero, we can conclude that:
View answer and explanationWhich of the following values can the coefficient of determination (R-squared) NOT take?
View answer and explanationStandard Error of Estimate (SEE) measures:
View answer and explanationIf a regression has an SSE of 200 and n = 22, what is the MSE?
View answer and explanationIn simple linear regression, the F-statistic is always a:
View answer and explanationThe intercept term in a regression is best interpreted as:
View answer and explanationUsing a 5 percent significance level with 34 degrees of freedom, the critical t-value is approximately 2.03. If the calculated t-statistic is 2.46, you should:
View answer and explanationWhich of the following indicates a stronger linear relationship?
View answer and explanationIf a regression has R-squared of 0.64, what is the correlation coefficient?
View answer and explanationThe Sum of Squared Errors (SSE) measures:
View answer and explanationA confidence interval for a predicted Y-value relies on:
View answer and explanationIn a regression model Y = b0 + b1*X + error, the term 'error' represents:
View answer and explanationIf a slope coefficient is 0.64, it implies that:
View answer and explanationIn the context of the F-test, Mean Regression Sum of Squares (MSR) is calculated as:
View answer and explanationIf the correlation between X and Y is negative, the slope coefficient of the regression of Y on X must be:
View answer and explanationA confidence interval for the predicted value of Y becomes wider when:
View answer and explanationWhich assumption is violated if the variance of the residuals increases as the predicted values increase?
View answer and explanationCalculate the t-statistic for a slope of 1.2 with a standard error of 0.4.
View answer and explanationIn the ANOVA table for simple regression, the Total Sum of Squares (SST) degrees of freedom is:
View answer and explanationIf RSS = 80 and SSE = 20, what is the value of R-squared?
View answer and explanationPrediction intervals are generally wider than confidence intervals because:
View answer and explanationIf a company uses a regression model to predict sales based on advertising spend, 'Sales' is the:
View answer and explanation