Doctors Studying How the Human Body Assimilates Medication Inject Some

Doctors studying how the human body assimilates medication inject some patients with penicillin,and then monitor the concentration of the drug (in units/cc)in the patients' blood for seven hours.The data are shown in the scatterplot.First they tried to fit a linear model.Now the researchers try a new model,using the re-expression log(Concentration).Examine the regression analysis and the residuals plot below.Explain why you think this model is better than the original linear model.