Table 1. Paired t-tests showing the simple effects of time on in-game spending at each level of problem gambling severity.

Problem gambling severity	t	df	p-value	In-game spending before the removal of loot boxes	In-game spending after the removal of loot boxes	Mean difference (reduction in spending)	Cohen’s d	Equivalent η2
Non-problem gamblers	0.033	58	1	$8.47($2.79–$14.15)	$8.47($3.41–$13.53)	$0.00	0	0
Low-risk gamblers	1.752	28	0.090	$11.37($5.54–$17.21)	$6.58($2.24–$10.93)	$4.79	0.325	0.025
Moderate-risk gamblers	−0.439	8	0.181	$21.11($6.63–$35.59)	$38.88($-0.15–$77.93)	-$17.77	0.488	0.056
Problem gamblers	2.420	14	0.029	$83.86($30.31–$137.41)	$48.46($0.15–$96.77)	$35.40	0.624	0.088