1. What are the input and the output of linear regression?
2. What does the coefficient of determination measure?
3. What is the purpose of measuring correlation?
4. Answer the following questions using this data.
A sales manager for an advertising agency believes there is a relationship between the number of contacts and the amount of the sales. To verify this belief, the following data was collected:
What is the dependent variable?
What is the independent variable?
What is the Y-intercept of the linear equation?
What is the slope of the linear equation?
What is the value of the coefficient of correlation?
5.The relationship between interest rates as a percent (X) and housing starts (Y) is given by the linear equation Y^ = 4094 - 269X. Answer these questions.
What will be the number of housing starts if the interest rate is 8.25%?
What will be the number of housing starts if the interest rate rose to 16%?
What happens to housing starts as interest rates fall?
6. If the regression equation is Y^ = 2 - 0.4X, what is the value of Y^ when X = -3?
7. In the least squares equation, Y^ = 10 + 20X the value of 20 indicates
8. If all the plots on a scatter diagram lie on a straight line, what is the standard error of estimate?
9. Based on the regression equation, we can
A) predict the value of the dependent variable given a value of the independent variable.
B) predict the value of the independent variable given a value of the dependent variable.
C) measure the association between two variables.
D) all of the above.
10. What is the general form of the regression equation?
A) Y^ = ab
B) Y^ = a + bX
C) Y^ = a - bX
D) Y^ = abX
11. The strength of the correlation between two variables depends on the sign of the coefficient of correlation.
True or False
12. The correlation coefficient is the proportion of total variation in Y that is explained by X. True or False
13. What does a coefficient of correlation of 0.70 infer?
A) Almost no correlation because 0.70 is close to 1.0
B) 70% of the variation in one variable is explained by the other
C) Coefficient of determination is 0.49
D) Coefficient of non-determination is 0.30
14. If we are studying the relationship between high school performance and college performance, and want to predict college performance, what kind of variable is high school performance? ________________
15. The regression coefficient, a, is the point where the regression line __________ the Y-axis.