A regression model is desired relating temperature and the proportion of impurity from a solid substance passing through solid helium. Temperature is listed in degrees centigrade. The data are as presented here.

(a) Fit a linear regression model.

(b) Does it appear that the proportion of impurities passing through helium increases the temperature as it approaches ?273 degrees centigrade?

(c) Find R².

(d) Based on the information above, does the linear model seem appropriate? What additional information would you need to better answer that question?

Temperature (C) -260.5 Proportion of Impurity 425 -255.7 -264.6 -265.0 -270.0 -272.0 .224 453 475 .705 .860 .935 961 .979 990 -272.5 -272.6 -272.8 -272.9