Students who rarely smoked marijuana mistakenly carried on with the old sorting rule on about 5 out of 100 occasions,while heavy users made about 8 mistakes.

• 偶尔抽大麻的学生每100次中大约有五次错误地沿用了旧的分类原则，而吸食成瘾的学生则大约要犯八次错误。