Solutions for Introduction to Probability and Statistics Test Bank . Questions with correct and verified answers. A+ GRADED.

Solutions for Introduction to Probability and Statistics Test Bank . Questions with correct and verified answers. A+ GRADED. TRUE/FALSE 1. If the correlation coefficient , then all the data points lie exactly on a straight line. ANS: T PTS: 1 2. The correlation coefficient r is a number that indicates the direction and the strength of the relationship between the dependent variable y and the independent variable x. ANS: T PTS: 1 3. If the correlation coefficient , then there is no linear relationship whatsoever between the dependent variable y and the independent variable x. ANS: T PTS: 1 4. A perfect straight line sloping upward would produce a covariance value of +1. ANS: T PTS: 1 5. A perfect straight line sloping downward would produce a covariance value of –1. ANS: T PTS: 1 6. The standard deviation is a measure of the linear relationship between two quantitative variables. ANS: F PTS: 1 7. Generally speaking, if two quantitative variables are unrelated, the covariance will be a positive or negative number close to zero. ANS: T PTS: 1 8. The best fitting line relating the dependent variable y to the independent variable x, often called the regression or least-squares line, is found by minimizing the sum of the squared differences between the data points and the line itself. ANS: T PTS: 1 9. The scatterplot is a graph that is used to graphically represent the relationship between two quantitative variables. ANS: T PTS: 1 10. When constructing a scatterplot, the independent variable (x) is placed on the horizontal axis, and the dependent variable (y) is placed on the vertical axis. ANS: T PTS: 1 11. A scatterplot is not particularly useful in determining if the relationship between the independent and dependent variables is not linear. ANS: F PTS: 1 12. If the linear relationship between the dependent and independent variables is positive, the scatterplot will show the data points on the (x, y) plane generally moving from the lower left corner to the upper right corner. ANS: T PTS: 1 13. If the correlation coefficient between the independent variable x and the dependent variable y is 0.87, then the best fitting line would have a slope equal to 0.87. ANS: F PTS: 1 14. If two variables have a correlation coefficient equal to 0.005, this means that there is no relationship between the two variables. ANS: F PTS: 1 15. A perfect correlation between two variables will always produce a correlation coefficient of +1.0. ANS: F PTS: 1 MULTIPLE CHOICE 1. Which of the following are measures of the linear relationship between two variables? a. the covariance b. the correlation coefficient c. the variance d. both the covariance and the correlation coefficient e. both the correlation coefficient and the variance ANS: D PTS: 1 2. Generally speaking, if two variables are unrelated (as one increases, the other shows no pattern), the covariance will be: a. a large positive number b. a large negative number c. a positive or negative number close to zero d. a positive or negative number close to 100 e. none of these ANS: C PTS: 1 3. Given the least squares regression line y = 3.8 – 2x, a. the relationship between x and y is positive b. the relationship between x and y is negative c. there is no linear relationship between x and y d. as x decreases, so does y e. as x increases, so does y ANS: B PTS: 1 Given that a. 0.70 = 400, = 625, = 350, and n = 10, the correlation coefficient is: b. 0.56 c. 0.875 d. 0.156 e. 0.141