The well-known psychologist Dr. Elbod has established what he calls his Generalized Anxiety Scale (GAS). The GAS, which is a scale from 0 to 10, measures the "general anxiety" of an individual, with higher GAS scores corresponding to more anxiety. (Dr. Elbod's assessment of anxiety is based on a variety of measurements, both physiological and psychological.)

The bivariate data below give the GAS score (denoted by x) and the number of hours of sleep last night (denoted by y) for each of the fifteen adults in a study. The least-squares regression line for these data has equation y= 8.49- 0.28x.This line, along with a scatter plot of the sample data, is shown below.

GAS score,x	Sleep time,y (in hours)
5.1	6.1
8.1	5.3
1.5	8.8
9.2	6.1
4.0	8.4
3.1	7.1
3.5	7.7
4.1	6.9
6.8	6.6
6.0	8.0
6.6	5.8
8.9	5.5
2.0	8.2
0.9	7.4
8.2	7.3