### Home > CCA2 > Chapter Ch11 > Lesson 11.2.4 > Problem11-75

11-75.

The principal at Algieres High School believes that over $20\%$ of students are text-messaging at least once a week during class. He believes this is an impediment to effective learning. Students claim that the actual percentage is much lower and that stricter rules are not necessary. Mrs. Rahil secretly observed her homeroom class very carefully for a week; only $13\%$ of students actually text-messaged during class. Assuming her homeroom is representative of the whole school, Mrs. Rahil’s class did a computer simulation and determined a margin of error of $10\%$. Is it plausible that the principal is correct and $20\%$ of the whole school is text-messaging?

Students can be assumed to be text-messaging $13\%\pm10\%$ of the time.