QUESTION 5 (20 Marks) a) Explain with the example the difference between point estimator and interval estimator. (2 Marks) b) A survey was conducted to find out the opinion of the general public on whether the individual smoker or society should bear the medical cost of smoking-related illness. In a random sample of 200 people, 128 were of the view that society should bear the cost of medical treatment. Estimate with 95% confidence, the true proportion of people who were of the opinion that society should bear the medical cost of smoking related illness. (8 Marks) c) A pharmaceutical company conducts an experiment to test the effect of a new cholesterol medication. The company selects 15 subjects randomly from a larger population. Each subject is randomly assigned to one of three treatment groups. Within each treatment group, subjects receive a different dose of the new medication. In Group 1, subjects receive 0 mg/day; in Group 2, 50 mg/day; and in Group 3, 100 mg/day. At a=0.05 does dosage level have a significant effect on cholesterol level? Group 1 (0 mg): 210, 240, 270, 270,300 Group 2 (50mg): 210, 240, 240, 270,270 Group 3 (100mg): 180, 210, 210, 210,240 (10 Marks)