The Essentials of Statistics 3rd Edition by Joseph Healey

تمرين 2

SOC: The students at Littlewood Regional High School cut an average of 3.3 classes per week. A random sample of 117 seniors averages 3.8 cuts per week, with a standard deviation of 0.53. Are seniors significantly different from the student body as a whole? (Hint: The wording of the research question suggests a two-tailed test. This means that the alternative, or research, hypothesis in step 2 will be stated as H 1 : µ ? 3.3 and that the critical region will be split between the upper and lower tails of the sampling distribution. See Table 7.1 for values of Z(critical) for various alpha levels.)