Logistic Regression: A Self-learning Text, Third Edition (Statistics in the Health Sciences)

(vip2019) #1

  1. For the model in Question 11, is a test for the
    significance of the two-factor product term SMK
    NS dependent on the coding of SMK? If so, explain
    why; if not, explain why not.

  2. For the model in Question 11, briefly describe a
    hierarchical backward elimination procedure for
    obtaining a best model.

  3. Suppose that the three-factor product term SMKNS
     AS is found significant during the interaction
    assessment stage of the analysis. Then, using the
    hierarchy principle, what other interaction terms
    must remain in any further model considered? Also,
    using the hierarchy principle, what potential
    confounders must remain in any further models
    considered?

  4. Assuming the scenario described in Question 15 (i.e.,
    SMKNSAS is significant), what (reduced) model
    remains after the interaction assessment stage of the
    model? Are there any potential confounders that are
    still eligible to be dropped from the model? If so,
    which ones? If not, why not?


200 6. Modeling Strategy Guidelines

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