Table 1.

Parameters estimates of the linear regression model explaining the ratio provided by the Raschpower method

Variables	N POP  = 984722	P-values
Intercept	1.012 (7.0 10−5)	<10−3
1/σ2	0.095 (1.0 10−4)	<10−3
1/J	0.939 (5.0 10−4)	<10−3
Interaction (1/σ2*1/J)	3.730 (7.5 10−4)	<10−3
R2	0.994	/
RMSE	0.030	/

Standard errors in parentheses. σ²: variance of the latent trait; J: number of items.