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help for ^symmetry^                                      (Statalist distribution)
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Symmetry and Marginal Homogeneity test for matched samples/ TDT test
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 ^symmetry^ var_cases var_controls [^if^ exp] [^in^ range] [^,^ ^not^able ^con^trib ^ex^act]



Description
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^symmetry^ performs symmetry and marginal homogeneity tests on square NxN
tables where there is a 1 to 1 matching of cases and controls
(non-independence).  In genetics, the test is known as the
Transmission/Disequilibrium test (TDT) and is used to test the association
between transmitted and non-transmitted parental marker alleles to an affected
child.


Options
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^notable^ suppresses the output of the contingency table. 

^contrib^ reports the contribution of each off-diagonal cell-pair to the
    overall symmetry chi-square.

^exact^ performs an exact test of table symmetry. CAUTION:  the exact test
    requires substantial amounts of time and memory for large tables.


Examples
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 . ^symmetry cases controls^
 . ^symmetry cases controls, not^
 . ^symmetry cases controls, con^
 . ^symmetry cases controls, not con^
 . ^symmetry cases controls, ex  con^


Author
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Mario Cleves <mcleves@@stata.com>.


Also see
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On-line:  @epitab@