An alternative goodness-of-fit test when at least one predictor is continuous partitions values for the explanatory variables into a set of regions and adds a dummy variable to the model for each region. The test statistic compares the fit of this model to the simpler one, testing that the extra parameters are not needed. Doing this for model (5.5.2) by partitioning according to the eight width regions in Table 5.2, show that the likelihood-ratio statistic for testing that the extra parameters are unneeded equals 7.5, based on df = 7.