They're nuanced concepts that are easily misunderstood, but in a typical US public school, statistical significance (or anything beyond basic descriptive statistics) is not typically part of the curriculum[1]. It's a hard problem to effectively educate out of existence but right now we're not even really trying.

[1] source: I never saw it as a student, and I've consulted with math teachers (well, administrators, about math) in multiple states, and I've never had it come up there either.