Preface to First Edition - lib

116 SIMPLE AND MULTIPLE LINEAR REGRESSIONEx. 6.5 Remove the observations for galaxies having leverage greater than0.08 and refit the zero intercept model. What is the estimated age of theuniverse from this model?Ex. 6.6 Fit a quadratic regression model, i.e, a model of the formvelocity = β 1 × distance + β 2 × distance 2 + ε,to the hubble data and plot the fitted curve and the simple linear regressionfit on a scatterplot of the data. Which model do you consider most sensibleconsidering the nature of the data? (The ‘quadratic model’ here is stillregarded as a linear regression model since the term linear relates to theparameters of the model not to the powers of the explanatory variable.)© 2010 by Taylor and Francis Group, LLC