The time to complete a standardized exam is approximately normal with a mean of 70 minutes and a standard deviation of 10 minutes. How much time should be given to complete the exam so that 90% of the students complete the exam in the allotted time?

Question

The time to complete a standardized exam is approximately normal with a mean of 70 minutes and a standard deviation of 10 minutes.  How much time should be given to complete the exam so that 90% of the students complete the exam in the allotted time?

tkhunny · Answer

Why are you posting this twice?

anonymous · Answer

I misposted it initially.  I threw it up on Mathematics until I realized that there was a Statistics subgroup. Its my mistake.