### Home > CCA2 > Chapter 11 > Lesson 11.2.4 > Problem 11-75

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? Homework Help ✎

Students can be assumed to be text-messaging 13% ± 10% of the time.