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. Author manuscript; available in PMC: 2011 Aug 2.
Published in final edited form as: Lang Speech Hear Serv Sch. 2009 Nov 30;41(1):118–128. doi: 10.1044/0161-1461(2009/08-0052)

Table 2.

Group correlations based on the degree of genetic relatedness (R) between kinship pairs for each of the cognitive achievement tests.

Degree of relatedness
Variable Cousins
R =.125		 Half-siblings
R =.25		 Unknown siblings
R =.375		 Full siblings
R =.50		 Identical twins
R =1.00
PIAT–RC .34 .28 .52 .47 .86
PIAT–RR .29 .35 .46 .42 .83
PIAT–M .24 .19 .40 .40 .72
PPVT–R .45 .25 .65 .61 .91