The number of minutes that it takes students to fill out an online survey has an approximately normal distribution with mean 11 minutes and standard deviation 2.5 minutes.
a. What percent of students take more than 12 minutes to fill out the survey?
b. What percent of student take between 9 and 14 minutes to fill out the survey?
c. 75% of students fill the survey in less than how many minutes?
d. 80% of students will be within how many standard deviations of the mean?
