1. Given the following sample data:
|
x
|
420
|
610
|
625
|
500
|
400
|
450
|
550
|
650
|
480
|
565
|
|
y
|
2.80
|
3.60
|
3.75
|
3.00
|
2.50
|
2.70
|
3.50
|
3.90
|
2.95
|
3.30
|
a. Calculate the covariance and the correlation coefficient.
b. Comment on the relationship between X and Y.
c. Determine the least-squares regression line (Use Excel data analysis toolpak).
d. Draw the scatter diagram and plot the least-squares line.
2. A car dealer wants to find the relationship between the odometer reading and the selling price of used cars. A random sample of 100 cars is selected and the data are recorded in the Excel file XM18-03. Estimate a linear relationship between price and odometer reading. Calculate the standard error of estimate and describe what it tells you about the model fit. Find the coefficient of determination. What does this statistic tell you about the model?