One of the founders of a society for skeptics believes that people would benefit from a more questioning attitude about various claims that people make and he has developed a course to teach such skills. A standardized skepticism assessment has a m = 90 and a s = 20. A sample of n = 40 is obtained from students who have taken his course and their mean is M = 99.

a.Employ the four-step hypothesis testing procedure to determine the effectiveness of the course using a two-tailed z-test and an a = .01.

b.If a significant difference was found, determine the size of the effect.