In: Statistics and Probability
The time to complete a standardized exam in the BYU-Idaho Testing Center is approximately normal with a mean of 70 minutes and a standard deviation of 10 minutes. Using the 68-95-99.7 rule, approximately what percentage of students will complete the exam in under fifty minutes? Give your answer accurate to one decimal place. (Example: 24.7)
the answer is 2.5 but how?