Normal calculation
A Canadian survey asked grad school students about the weekly time they spend studying outside the classroom. The time spent studying in minutes follows a normal distribution with mean 720 minutes and standard deviation 120 minutes.
a) What can you say about the study time range of the middle 95% students?
b) Find the percentage of students who might study less than 500 minutes.
c) What study time would be such that 20% of students study more than it?
Answer the questions by-hand first, and then using Excel. Sketch the density curves that support your answers