Final answer:
The given question is about cubic regression analysis and finding the correlation coefficient.
Step-by-step explanation:
a. The independent variable is the x-coordinate (7, 10, 0) and the dependent variable is the y-coordinate (11, -16, 4).
b. To calculate the least-squares line, we use regression analysis to find the equation of the cubic regression curve: y = a + bx + cx^2 + dx^3.
c. We plot the data points on a scatter plot and draw the regression curve on top of it.
d. The correlation coefficient measures the strength and direction of the relationship between the variables. If it is close to 1 or -1, the relationship is strong, and if it is close to 0, the relationship is weak.
e. To find the average CPI for the year 1990, we would need more information as the given data is not related to CPI.