Table 3.

Confidence intervals for parameters of the regression analyses for the correlation of the Raven items with WMC (calculated from the short-term memory and relation integration tasks; N = 939) over difficulty of the items.

Regression	Parameter	Point estimation value	95% confidence interval
Linear [F(1, 34) = 0.55)	Intercept	0.19	[0.16, 0.21]
	Slope	−0.019	[−0.07, 0.032]
Quadratic [F(2, 33) = 6.22]	Intercept	0.14	[0.11, 0.17]
	Linear term coefficient	0.31	[0.11, 0.5]
	Quadratic term coefficient	−0.38	[−0.6, −0.15]
Segmented [F(3, 32) = 13.5]	Intercept	0.15	N/A
	Breakpoint	0.42	[0.17, 0.66]
	Slope before breakpoint	0.15	[0.0036, 0.65]
	Slope after breakpoint	−0.35	[−0.46, −0.065]

Point estimation values are values of parameters fitted by regression which do not take in the account the error of estimation.