TABLE 1.

Descriptive statistics of the central variables.

Variable	Condition
	Worked-examples		Problem-solving
	M(SD)	95% CI	M(SD)	95% CI
In-class Session 1
Initial performance expectancy in points4	23.20 (7.94)	[20.27; 25.98]	18.87 (10.09)	[15.30; 22.35]
Test performance in points	14.13 (5.30)	[12.39; 16.08]	17.24 (6.85)	[15.07; 19.69]
In-class Session 2
Test performance in points	12.50 (6.58)	[10.49; 14.90]	14.25 (7.62)	[11.81; 16.93]

95% CI is based on bootstrapping with 1000 samples. All initial performance expectancies and both post-test points ranged from 0 to 42 points. ⁴When Initial performance expectancy is computed as mean of PS1-PE1 and PS1-PE2, summed with PS2-PE1 (that is with the initial performance expectancy after receiving an example solution averaged), the values are similar, M = 23.54, SD = 8.01, 95% CI [20.70, 26.19]. Performance expectancies prior and after seeing the example solution (PS1-PE1 and PS1-PE2) are not statistically different in both groups (Worked example: t(31) = −0.97, p = 0.34, MD = −0.67, SD = 3.91, 95% CI [−2.08, 0.74], d_Cohen = 0.09; Problem solving: t(28) = −1.45, p = 0.16, MD = −1.17, SD = 4.37, 95% CI [−2.83, 0.49], d_Cohen = 0.13).