According to the linked article, the survey question was" How many times have you felt stressed out about school in the last week?"
I remember a number of years ago an affluent high school in my county was reported to be the highest in some survey for alcohol or drug use over the last week; something along those lines… Naturally the local people were alarmed, and there were follow up meetings about it at their high school. It turned out the survey for that school was taken the week the students returned from spring break.
Some time ago on CC a prospective applicant to my alma mater reported that they were turned off because when they visited nobody was out and about chilling, and people looked stressed. Various alums were giving their takes, then finally a current student chimed in with “Dude, you visited during prelim (a.k.a. exam) week . everybody was studying…”
Probably at most schools you can find a week where most students are preoccupied with academics… But you can find other weeks where it would be a lot less the case.