4. Answer True or False for the following statements. Justify your answer if False.

a. If the least-squares equation relating the independent variable x and the dependent variable y

for a given problem is y = 2x+5, then an increase of 1 unit in x is associated with an increase of

2 units in y.

b. The coefficient of determination R2 measures the variation in the dependent variable that is

explained by the regression model.

c. If your computed correlation coefficient is r = +1.2, then you have better than a perfect positive

correlation.

d. A student might expect that there is a positive correlation between the age of his or her

computer and its resale value.

e. In simple regression analysis, if the slope of the line is positive, then there is a positive

correlation between the dependent variable y and the independent variable x.

f. The coefficient of determination can assume negative values.

g. A negative correlation indicates that as values of x are increased, values of y will decrease.

h. If there is no correlation between the independent and dependent variables, then the value of

the correlation coefficient must be -1.