Unit V review

V-2 __ 7. A statistics professor wants to see if more than 80% of her students enjoyed taking her class. At the end of the term, she takes a random sample of students from her large class and asks, in an anonymous survey, if the students enjoyed taking her class. Which set of hypotheses should she test? A) H H 0 A : . : . p p < > 0 80 0 80 B) H H A 0 0 80 0 80 : . : . p p = > C) H H 0 A : . : . p p > = 0 80 0 80 D) H H 0 A : . : . p p < ≠ 0 80 0 80 E) H H 0 A : . : . p p = < 0 80 0 80 __ 8. Not wanting to risk poor sales for a new soda flavor, a company decides to run one more taste test on potential customers, this time requiring a higher approval rating than they had for earlier tests. This higher standard of proof will increase I. the risk of Type I error II. the risk of Type II error III. power A) I only B) II only C) III only D) I and II E) I and III __ 9. Suppose that a manufacturer is testing one of its machines to make sure that the machine is producing more than 97% good parts H and H 0 A : . : . p p = > ( ) 0 97 0 97 . The test results in a P -value of 0.122. Unknown to the manufacturer, the machine is actually producing 99% good parts. What probably happens as a result of the testing? A) They correctly fail to reject H 0 . B) They correctly reject H 0 . C) They reject H 0 , making a Type I error. D) They fail to reject H 0 , making a Type I error. E) They fail to reject H 0 , making a Type II error. __10. Which of the following is true about Type I and Type II errors? I. Type I errors are always worse than Type II errors. II. The severity of Type I and Type II errors depends on the situation being tested. III. In any given situation, the higher the risk of Type I error, the lower the risk of Type II error. A) I only B) II only C) III only D) I and III E) II and III 11. Approval rating The President’s job approval rating is always a hot topic. Your local paper conducts a poll of 100 randomly selected adults to determine the President’s job approval rating. A CNN/ USA Today /Gallup poll conducts a poll of 1010 randomly selected adults. Which poll is more likely to report that the President’s approval rating is below 50%, assuming that his actual approval rating is 54%? Explain.