Table 1.

Prevalence of Past 30–day Marijuana Vaping Among Students, Stratified by Grade

Grade	Sample size	Past 30 day Has not used marijuana	p- value	Past 30 day Has vaped marijuana	p- value	Past 30 day Has used marijuana (not vaped)	p- value
Past 30–day marijuana vaping (full sample); N=9,131
8th	4,465	94.1 (4,057)	<0.001	2.7 (120)	<0.001	3.8 (158)	<0.001
10th	4,666	83.6 (3,762)	<0.001	7.2 (363)	<0.001	10.4 (435)	<0.001
Past 30–day marijuana vaping (complete case analysis); N=5,755
8th	2,582	94.1 (2,430)	<0.001	2.4 (61)	<0.001	3.9 (99)	<0.001
10th	3,173	83.0 (2,632)	<0.001	8.7 (275)	<0.001	10.1 (293)	<0.001

Notes: Boldface indicates statistical significance (p<0.001 for all prevalence estimates). Estimated prevalence of different categories of past 30–day marijuana use (i.e., no marijuana use, marijuana vaping only, marijuana use only) for each grade level for 2 different samples shown in Table 1. The 3 categories are mutually exclusive: the first column checks associations of each grade with no marijuana use, the second column with past 30–day marijuana vaping, and the third with past 30–day marijuana use (not vaped). The first rows depict prevalence for the full sample and the following rows show prevalence for the complete case analysis. Displayed percentages. Sample size in parenthesis.

Source: Monitoring the Future Survey, 2018.