In an experiment to determine corrosion rates, steel plates were placed in a solution of 10% hydrochloric acid (HCl) for various periods of time (in hours), and the weight loss (in mg) was measured. Following are the results.
| Time |
2 |
4 |
6 |
8 |
10 |
12 |
| Weight loss |
0.3 |
6.9 |
7.2 |
11.9 |
16.2 |
22.5 |
a. Compute the least-squares line for predicting the weight loss (y) ata given time (x ).
b. Should the line be used to predict the weight loss after 1 hour? If so, predict the weight loss. If not, explain why not.
c. Should the line be used to predict the weight loss after 5 hours? If so, predict the weight loss. If not, explain why not.
d. Should the line be used to predict the weight loss after 20 hours? If so, predict the weight loss. If not, explain why not.
sum of squares is ),(yi - yˆi )2 = 33.9, compute the coefficient of determination r 2 .