Employees in a large company are entitled to 15-minute coffee breaks. A random sample of the duration of coffee breaks for ten employees was taken, with the times shown as: 12, 16, 14, 18, 21, 17, 19, 15, 18, and 16. Assuming that the times are normally distributed, is there enough evidence at the 5% significance level to indicate that on average employees are taking longer coffee breaks than they are entitled to? (11 marks)