An article gave a scatter plot along with the least squares line of x = rainfall volume (m3) and y = runoff volume (m3) for a particular location. The accompanying values were read from the plot.
| x |
7 |
12 |
14 |
19 |
23 |
30 |
40 |
50 |
55 |
67 |
72 |
81 |
96 |
112 |
127 |
| y |
4 |
10 |
13 |
15 |
15 |
25 |
27 |
45 |
38 |
46 |
53 |
75 |
82 |
99 |
104 |
The point estimate of the slope and intercept of the population regression line. Slope = .85704, Intercept = -2.59469. The point estimate of the true average runoff volume when the rainfall volume is 47 is = 37.6862 m3
(a) Calculate a point estimate of the standard deviation. (Round your answer to two decimal places.)
(b) What proportion of the observed variation in runoff volume can be attributed to the simple linear regression relationship between runoff and rainfall? (Round your answer to four decimal places.)