Table 5.13 refers to the effectiveness of immediately injected or -hourdelayed penicillin in protecting rabbits against lethal injection with β-hemolytic streptococci.
a. Let X = delay, Y = whether cured, andZ = penicillin level. Fit the model, deleting an intercept term so each level of Z has its own parameter. Argue that the pattern of 0 cell counts suggests that What does your software report?
b. Using the logit model, conduct the likelihood-ratio test of XY conditional independence. Interpret.
c. Estimate the XY conditional odds ratio. Interpret.
