University of California Press

Table 4.

Paired t-test comparisons of students’ overall performance (percentage) on pretests and posttests, by semester.

	Fall 2016	Spring 2017	Fall 2017	Spring 2018
Pretest percentage (⁠ $\bar{X}$ ± SE)	77 ± 2	66 ± 2	67 ± 2	71 ± 2
Posttest percentage (⁠ $\bar{X}$ ± ± SE)	91 ± 1	77 ± 3	80 ± 3	84 ± 2
n	107	55	65	71
t	8.878	3.786	5.504	7.439
p	<0.001	<0.001	<0.001	<0.001
Cohen's d	0.858	0.511	0.683	0.883

	Fall 2016	Spring 2017	Fall 2017	Spring 2018
Pretest percentage (⁠ $\bar{X}$ ± SE)	77 ± 2	66 ± 2	67 ± 2	71 ± 2
Posttest percentage (⁠ $\bar{X}$ ± ± SE)	91 ± 1	77 ± 3	80 ± 3	84 ± 2
n	107	55	65	71
t	8.878	3.786	5.504	7.439
p	<0.001	<0.001	<0.001	<0.001
Cohen's d	0.858	0.511	0.683	0.883