Consider the following data set. 6.8, 9.1, 8.7, 7.5, 8.2, 5.4, 6.5, 8.5, 7.3, 6.6, 5.9, 7.3, 9.3, 7.5, 7.8 Calculate the sample standard deviation. Round your answer to 2 decimals as needed.