Polychoric correlation coefficient for cognitive impairment defined by MMSE score.

	Mild	No	Severe
type	polychoric	polychoric	polychoric
rho	−0.02262085	0.5264594	0.6680286
var	0.02782513	0.007320261	0.01047318
n	41	72	27
chisq	89.31905	84.63891	58.79614
df	107	119	109
ML	FALSE	FALSE	FALSE