* School size: A large high school will generate far more litter than a small elementary school.
* Student population: A school with a student body known for being responsible will have less litter than one with a less attentive student body.
* School policies and enforcement: Schools with robust recycling programs and consequences for littering will have less litter.
* Campus design and facilities: Adequate trash and recycling receptacles make a difference.
* Day of the week: There might be more litter on days with more events or outdoor activities.
* Weather: Nice weather might encourage more outdoor eating and thus more litter.
To get an accurate measurement for a specific school, you'd need to conduct a litter audit – measuring the amount of litter collected at the end of a school day, accounting for pre-existing litter. Even then, it's difficult to accurately quantify the amount dropped *during* the school day versus what was already present.
In short, it's impossible to give a numerical answer without specific data from a particular school.