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Introduction to Categorical Data Analysis

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CHAPTER 8: MODELS FOR MATCHED PAIRS 339<br />

Table A.11. SAS Code for Testing Marginal Homogeneity with Coffee <strong>Data</strong> of Table 8.5<br />

data migrate;<br />

input first $ second $ count m11 m12 m13 m14 m21 m22 m23 m24<br />

m31 m32 m33 m34 m41 m42 m43 m44 m55 m1 m2 m3 m4;<br />

datalines;<br />

high high 93 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0<br />

high tast 17 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0<br />

high sank 44 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0<br />

high nesc 7 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0<br />

high brim 10 -1 -1 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0<br />

...<br />

nesc nesc 15 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0<br />

nesc brim 2 0 0 0 0 0 0 0 0 0 0 0 0 -1 -1 -1 -1 0 0 0 0 1<br />

brim high 10 -1 0 0 0 -1 0 0 0 -1 0 0 0 -1 0 0 0 0 1 0 0 0<br />

brim tast 4 0 -1 0 0 0 -1 0 0 0 -1 0 0 0 -1 0 0 0 0 1 0 0<br />

brim sank 12 0 0 -1 0 0 0 -1 0 0 0 -1 0 0 0 -1 0 0 0 0 1 0<br />

brim nesc 2 0 0 0 -1 0 0 0 -1 0 0 0 -1 0 0 0 -1 0 0 0 0 1<br />

brim brim 27 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0<br />

;<br />

proc genmod;<br />

model count = m11 m12 m13 m14 m21 m22 m23 m24 m31 m32 m33 m34 m41<br />

m42 m43 m44 m55 m1 m2 m3 m4<br />

/ dist=poi link=identity obstats residuals;<br />

and columns). Here, m11 denotes expected frequency μ11, m1 denotes μ1+ = μ+1,<br />

and so forth. This parameterization uses formulas such as μ15 = μ1+ − μ11 − μ12 −<br />

μ13 − μ14 for terms in the last column or last row. The likelihood-ratio test statistic<br />

for testing marginal homogeneity is the deviance statistic for this model.<br />

Table A.12 shows analyses of Table 8.6. First the data are entered as a 4 × 4<br />

table, and the loglinear model fitted is quasi independence. The “qi” fac<strong>to</strong>r invokes<br />

Table A.12. SAS Code Showing Square-table Analyses of Tables 8.6<br />

data square;<br />

input recycle drive qi count ©©;<br />

datalines;<br />

1 1 1 12 1 2 5 43 1 3 5 163 1 4 5 233<br />

2 1 5 4 2 2 2 21 2 3 5 99 2 4 5 185<br />

3 1 5 4 3 2 5 8 3 3 3 77 3 4 5 230<br />

4 1 5 0 4 2 5 1 4 3 5 18 4 4 4 132<br />

;<br />

proc genmod; class drive recycle qi;<br />

model count = drive recycle qi / dist=poi link=log; ∗ quasi indep;<br />

data square2;<br />

input score below above ©©; trials = below + above;<br />

datalines;<br />

1 4 43 1 8 99 1 18 230 2 4 163 2 1 185 3 0 233<br />

;<br />

proc genmod data=square2;<br />

model above/trials = / dist=bin link=logit noint;<br />

proc genmod data=square2;<br />

model above/trials = score / dist=bin link=logit noint;

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