(31 Marks) In the R package faraway there is a data set called rats. This data...

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(31 Marks) In the R package faraway there is a data set called rats. This data resulted from a study conducted to determine the survival time of rats exposed to four different types of Poisons and Treatments. a. (12 Marks) Assuming that time follows an Inverse Gaussian distribution, fit an additive model. Give the AIC, residual deviance, and the associated p-value for D, for i. the canonical link (3 Marks) ii. the log-link (3 Marks) iii. the inverse link (3 Marks) iv. the identity link (3 Marks) b. Which model from a. appears to give the "best" fit? Explain. (2 Marks) c. For the model selected in b. is there evidence that the maximal model is required? Explain. (2 Marks) d. (9 Marks) Repeat a. using a Gamma GLM. Give the AIC, residual deviance, and the associated p-value for D, for i. the log-link (3 Marks) ii. the inverse link (3 Marks) iii. the identity link (3 Marks) e. Which model from d. appears to give the "best" fit? Explain. (2 Marks) f. Would you recommend the model from b. or e.? Explain. (2 Marks) g. For the model selected in e. interpret the effect of changing from the Poison I to Poison II. (2 Marks). (31 Marks) In the R package faraway there is a data set called rats. This data resulted from a study conducted to determine the survival time of rats exposed to four different types of Poisons and Treatments. a. (12 Marks) Assuming that time follows an Inverse Gaussian distribution, fit an additive model. Give the AIC, residual deviance, and the associated p-value for D, for i. the canonical link (3 Marks) ii. the log-link (3 Marks) iii. the inverse link (3 Marks) iv. the identity link (3 Marks) b. Which model from a. appears to give the "best" fit? Explain. (2 Marks) c. For the model selected in b. is there evidence that the maximal model is required? Explain. (2 Marks) d. (9 Marks) Repeat a. using a Gamma GLM. Give the AIC, residual deviance, and the associated p-value for D, for i. the log-link (3 Marks) ii. the inverse link (3 Marks) iii. the identity link (3 Marks) e. Which model from d. appears to give the "best" fit? Explain. (2 Marks) f. Would you recommend the model from b. or e.? Explain. (2 Marks) g. For the model selected in e. interpret the effect of changing from the Poison I to Poison II. (2 Marks).

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a i Canonical Link AIC 51990 Residual Deviance 41190 pvalue for D 008 ii LogLink AIC 52215 Residual ... View the full answer