The life in hours of a laser is known to be normally distributed with a standard deviation of sigma = 20 hours. A sample of 15 lasers and their lives is as follows: 708, 692, 736, 707, 708, 696, 708, 693, 705, 701, 734, 684, 707, 722, 694. a). Is there evidence to support the claim that the mean life does not equal 695 hours? Use alpha = .1 b) What is the beta value if the true mean life is 715 hours? Please show work.