Answer Happy

Question B5 Suppose a doctor wishes to estimate the mean total cholesterol level of people working in a certain industry. A random sample of 3,310 people working in this industry were then selected and found that the mean and the standard deviation of total cholesterol levels are 200.3 mg/dL and 36.8 mg/dL respectively. (a) Construct a 95% confidence interval for the true mean total cholesterol level of people working in this industry and show the checking/assumption if any. Correct the final answers to 1 decimal place. (4 marks) (b) Interpret the confidence interval obtained from part (a) above. (2 marks) (c) Based on the results from part (a), can the doctor claim that the true mean total cholesterol level of people working in this industry is equal to 200mg/dL at a 0.05 level of significance? (State the null hypothesis and rejection rule clearly.) (4 marks) (d) How many additional samples are required if the doctor wants to estimate the true mean total cholesterol level of people working in this industry with error within 1.5 mg/dL and with 99% level of confidence? (4 marks)