loglinear models and forward and backward selection method, attached the question. Table 10.9 summarizes a study with variables age of mother (A), length of ges-tation (G) in days, infant survival...

loglinear models and forward and backward selection method, attached the question.
Table 10.9 summarizes a study with variables age of mother (A), length of ges-tation (G) in days, infant survival (/), and number of cigarettes smoked per day during the prenatal period (S). Treat G and / as response variables and A and S as explanatory. a. Explain why a loglinear model should include the lAs term. b. Fit the models (AGIS). (AGI, MS, AGS, GIS), (AG, Al, AS, GI, GS, IS), and (AS. G, /). Identify a subset of models nested between two of these that may fit well. c. Use (i) forward selection and (ii) backward elimination to build a model between two of the models listed in (b). Compare the results of the strategies, and interpret the models chosen.