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Introduction to Categorical Data Analysis

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296 MODELING CORRELATED, CLUSTERED RESPONSES<br />

9.14 Analyze the depression data in Table 9.1 using a Markov transitional model.<br />

Compare results and interpretations <strong>to</strong> those in this chapter using marginal<br />

models.<br />

9.15 Table 9.13 is from a longitudinal study of coronary risk fac<strong>to</strong>rs in school<br />

children. A sample of children aged 10–13 in 1977 were classified by gender<br />

and by relative weight (obese, not obese) in 1977, 1979, and 1981. Analyze<br />

these data, summarizing results in a one-page report.<br />

Table 9.13. Children Classified by Gender and Relative Weight<br />

Responses a<br />

Gender NNN NNO NON NOO ONN ONO OON OOO<br />

Male 119 7 8 3 13 4 11 16<br />

Female 129 8 7 9 6 2 7 14<br />

Source: From R. F. Woolson and W. R. Clarke, J. R. Statist. Soc., A147: 87–99,<br />

1984. Reproduced with permission from the Royal Statistical Society, London.<br />

a NNN indicates not obese in 1977, 1979, and 1981, NNO indicates not obese in<br />

1977 and 1979, but obese in 1981, and so forth.<br />

9.16 Refer <strong>to</strong> the cereal diet and cholesterol study of Problem 6.16 (Table 6.19).<br />

Analyze these data with marginal models, summarizing results in a one-page<br />

report.<br />

9.17 What is wrong with this statement: “For a first-order Markov chain, Yt is<br />

independent of Yt−2”?<br />

9.18 True, or false? With repeated measures data having multiple observations<br />

per subject, one can treat the observations as independent and still get valid<br />

estimates, but the standard errors based on the independence assumption may<br />

be badly biased.

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