Exam 4: Regression Models

The null hypothesis in the F-test is that there is a linear relationship between the X and Y variables.

Often,a plot of the residuals will highlight any glaring violations of the assumptions.

Dummy variables for regression analysis can take on a value of either -1 or +1.

Transformations may be used when nonlinear relationships exist between variables.

In regression,the X variable is known as the ________ variable.

In regression,a dependent variable is sometimes called a predictor variable.

What can be said about a correlation coefficient of -1?

To include qualitative data in regression analysis,you must first create a ________ variable.

For statistical tests of significance about the coefficients,the null hypothesis is that the slope is 1.

A large school district is reevaluating its teachers' salaries.They have decided to use regression analysis to predict mean teacher salaries at each elementary school.The researcher would like to examine the significance of the following quadratic model for predicting salary based on years of experience. Y = β₀ + β₁X₁ + β₂X₂ + ε where X₁ = Yrs Exp and X₂ = Yrs Exp² (a)What is the adjusted r²? (b)What is the prediction equation?

In any regression model,there is an implicit assumption that a relationship exists between the variables.

In a good regression model the residual plot shows

Which of the following conditions can be detected from residual analysis?

The multiple regression model includes multiple slope coefficients.

A study was done to determine the relationship between GPA and starting salaries for college graduates.The data is shown in the table below: Use model building to determine the best fit based on highest adjusted r².

Error is the difference in the actual value and the predicted value.

The value of r² can never decrease when more variables are added to the model.

A large school district is reevaluating its teachers' salaries.They have decided to use regression analysis to predict mean teachers' salaries at each elementary school.The researcher uses years of experience to predict salary.The resulting equation was: Y = 23,313.22 + 1,210.89X,where Y = salary and X = years of experience (a)If a teacher has 10 years of experience,what is the forecasted salary? (b)If a teacher has 5 years of experience,what is the forecasted salary? (c)Based on this equation,for every additional year of service,a teacher could expect his or her salary to increase by how much?

An electronics company is looking to develop a regression model to predict the number of units sold for a special running watch.Data is provided below: A)Define the dummy variable(s)for the regression model. B)What is the correlation between the Holiday categorical variable and sales?

In regression,the variable to be predicted is called the ________ variable.