Twelve students enrolled in the course of business statistics were sampled at random. At the end of this course, I asked each student how much time they spent doing statistics assignments. This data is compiled in the following. Data are known to follow a normal distribution. The professor in this course recommended three hours per week for the 12-week term. Test whether there is evidence that students have spent less time on assignments than the professor recommended on average. Use a significance level of 0.05.

31 40 26 30 36 39 29 40 38 30 35 38