Ch4 - Sample Quiz Question 1. Suppose we have a bivariate set of data with over 1000 sample points. Which is not a valid value for r ? a) 1 b) 2 c) -1 d) 0 e) None of the above Question 2. What does a value r = −.910 indicate? a) Strong positive linear correlation b) Moderate positive linear correlation c) Strong negative linear correlation d) No linear correlation e) None of the above Question 3. If there is no linear correlation of the data, what value of r would you most expect to see? a) .589 b) -.432 c) .014 d) -.004 e) 1.000 Question 4. What kind of correlation does the scatter plot exhibit? a) Negative linear b) Positive linear c) Positive Quadratic d) Negative Quadratic e) No correlation Question 5. What kind of correlation does the scatter plot exhibit? a) Negative linear b) Positive linear c) Positive Quadratic d) Negative Quadratic e) No correlation Question 6. What kind of correlation does the scatter plot exhibit? a) Negative linear b) Positive linear c) Positive Quadratic d) Negative Quadratic e) No correlation Question 7. For this scatter plot, what value most closely represents the correlation coefficient? a) -.823 b) .580 c) .261 d) .917 e) None of the above are close to the actual correlation coefficient Question 8. The least-squares regression line seeks to minimize a) the sum of the squared residuals, where a residual is the difference between the observed y and the predicted y . b) overall effort in calculating correlation. c) the coefficient of determination. d) the number of observations that do not lie on the line. e) None of the above. Question 9. For a bivariate data set having a strong positive linear correlation, which is true? sx a) The slope of the line is close to . sy b) The correlation coefficient is the y -intercept. sy c) The slope of the line is close to . sx d) The point (sx , sy ) lies on the line. e) None of the above. Question 10. For any bivariate data set, which of the following is true? a) The correlation coefficient r = 1 only when there is a strong negative linear correlation. b) The point (x̄, ȳ ) lies on the least squares regression line. c) At least two points in the scatter plot lie on the least squares regression line. d) All of the above e) None of the above Question 11. The coefficient of determination measures a) how positive the linear relationship between the variables is. b) how determined the relationship between the variables is. c) how well the least squares regression line extrapolates beyond the observed variables. d) how well the least squares regression line describes the relationship between the variables. e) None of the above.