11. 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 know if the enrollment on their website is above 30% based on a small sample of customers. They test Ho: p = 0.3 vs. HA: p > 0.3 and reject the null hypothesis. Later they find 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 mar- keting company tests all students on campus and finds no difference. c) A human resource analyst wants to know if the applicants this year score, on average, higher on their placement exam than the 52.5 points the candidates averaged last year. She samples 50 recent tests and finds the average to be 54.1 points. She fails to reject the null hypothesis that the mean is 52.5 points. At the end of the year, they find that the candi- dates this year had a mean of 55.3 points. d) A pharmaceutical company tests whether a drug lifts the headache relief rate from the 25% achieved by the placebo. They fail 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.3. P-values Which of the following are true? If false, explain briefly. a) A very high P-value is strong evidence that the null hypoth- esis is false. b) A very low P-value proves that the null hypothesis is false. c) A high P-value shows that the null hypothesis is true. d) A P-value below 0.05 is always considered sufficient evidence to reject a null hypothesis.30. Quality control Production managers on an assembly line must monitor the output to be sure that the level of defective products remains small. They periodically inspect a random sample of the items produced. If they find a significant in- crease in the proportion of items that must be rejected, they will halt the assembly process until the problem can be iden- tified and repaired. a) In this context, what is a Type I error? b) In this context, what is a Type II error? c) Which type of error would the factory owner consider more serious? d) Which type of error might customers consider more seri- ous?40. Catheters During an angiogram, heart problems can be exam- ined via a small tube (a catheter) threaded into the heart from a vein in the patient's leg. It's important that the company that manufactures the catheter maintain a diameter of 2.00 mm. (The standard deviation is quite small.) Each day, quality con- trol personnel make several measurements to test H: u = 2.00 against H cu * 2.00 at a significance level of a = 0.05. If they discover a problem, they will stop the manufacturing process until it is corrected. a) Is this a one-sided or two-sided test? In the context of the problem, why do you think this is important? b) Explain in this context what happens if the quality control people commit a Type I error. c) Explain in this context what happens if the quality control people commit a Type II error