Table 7. Regression models.

	Observations deleted	Regression model	Adjusted $R^2$	${\sigma }^2$
1	None	$y=-0.15+0.1036x_1+0.0002x_2$	0.914	0.0599
2	7,11,18	$y=-0.18+0.1138x_1+0.0001x_2$	0.9721	0.0105
3	7, 18, 33	$y=-0.14+0.1105x_1+0.0001x_2$	0.9855	0.0062