Refer to the previous exercise. Table 6.7 shows output for a cumulative logit model with scores (1, 2, 3) for the income categories.

a. Explain advantages of this model over the baseline-category logit model of the previous exercise.

b. Does the model fit adequately? Justify your answer. Why does the output report two intercepts but one income effect?

c. Report a test statistic and P-value for testing that marital happiness is independent of family income. Interpret the income effect.

Table 6.7 Software output on modeling happiness for Exercise 6.7.

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Estimate Std. Error z value Pr(>|z|)

(Intercept):1 -3.2466 0.3404 -9.537 <2e-16

(Intercept):2 -0.2378 0.2592 -0.917 0.359 income -0.1117 0.1179 -0.948 0.343

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Residual deviance: 3.2472 on 3 degrees of freedom

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