2. A principal of high school was concerned with amount of time her students devote to working at after-school jobs. She randomly selected 25 students, obtained their working _ hours for 1 week and computed X = 12.5 hours and s = 3.9 hours. She claims that her students work significantly more than the mean of 10.7 hours from a study conducted by the National Association of State High School Association. Test her claim by using the 5% level of significance