I've been doing this problem for an hour and I keep getting the same answer!!! Please help!!

ect Question 2 0 / 1 pts The Instructor of a math class asked 10 of her Statistics students to report the number of hours they spent last night preparing for the in-class quiz. The following table contains the 10 responses: 2 hrs 2 hrs 4 hrs 3 hrs 3 hrs 4 hrs 2 hrs 5 hrs 5 hrs 4 hrs Calculate the sample standard deviation for the number of hours students spent preparing for the quiz. Round your answer to the nearest tenth of one hour. 7.1