Errors For each of the following situations, state whether a Type I, a Type II, or

Chapter 20, Problem 7

(choose chapter or problem)

Errors For each of the following situations, state whether a Type I, a Type II, or neither error has been made. Explain briefly. a) A bank wants to see if the enrollment on their website is above 30% based on a small sample of customers. It tests H0: p = 0.3 vs. HA: p 7 0.3 and rejects the null hypothesis. Later the bank finds out that actually 28% of all customers enrolled. b) A student tests 100 students to determine whether other students on her campus prefer Coke or Pepsi and finds no evidence that preference for Coke is not 0.5. Later, a marketing company tests all students on campus and finds no difference. c) A pharmaceutical company tests whether a drug lifts the headache relief rate from the 25% achieved by the placebo. The test fails to reject the null hypothesis because the P-value is 0.465. Further testing shows that the drug actually relieves headaches in 38% of people.