2. (20 pts) Hypothesis Testing: u-test The following sample 4, 3, 5, 5, -7, -13, -6, 11, 7 is drawn from a Gaussian population with variance o2 = 9. (a) It is supposed that the mean of this Gaussian population is 7 = 0. Can we reject this hypothesis (i.e. H : 7 = 0) with 95% confidence, based on the sampled data? (b) It is now supposed that the mean of this Gaussian population is 7 = 3. Can we reject this hypothesis (i.e. Hy i = 3) with 95% confidence, based on the sampled data? :