. An insurance dataset contains individual medical costs billed by US insurance companies and patient information, such as age, BMI (Body Mass Index) and smoking status. A sample of 58 smokers have been considered and the model below was fitted to estimate medical cost (Y, in thousands of dollars) from age (11) and BMI (22) Model 4: Y,=a+Bau + 97% +€, i=1,...,58, &~ N(0,0%), e's independent. Model 4 was fitted to the data and some extracts from the R output are displayed below. Regression Analysis: Cost versus Age, BMI Coefficients: Estimate Std. Error (Intercept) -27.69828 4.39041 Age 0.38223 0.05241 BMI 1.58192 0.13284 t value Pr>t) -6.387 5.11e-e6 5.767 3.82e-e7 11.909 < 2e-16 Analysis of Variance Table Response: Cost Sun Sg Model 5635.5 Residuals 1604.6