Question 4 20 marks Answer this question using the following information: P(0

Question 4 Answer this question using the following information: < z < 1.68) = 0.4535 "(0 < z < 2.12) 0.4830. where Z is thc standard normal random variable, 20 marks (a) (b) (C) A survey of 300 randomly selected customers of Company A found that (3 x R + 195) of them are satisfied with the service provided by the company. (i) Find the best point estimate of the proportion ofcustomers ofCompany A who are satisfied with thc service provided by the company. Correct your answers to 2 decimal places. (4 marks) (ii) Find the 96.6% confidence interval of the true proportion of customers who arc satisfied with the service provided by Company A. Correct your answers to 2 decimal places. (8 marks) The CEO ofa large company wishes to estimate, with 96.6% confidence. the true proportion ofcmployees of the company favouring a proposed flexible work policy. A previous study shows that 75% of the employees interviewed favoured the proposed policy. The CEO wishes to be accurate within (5 + of the true proportion. Find the minimum sample size required. (4 marks) The CEO in (b) has now moved to a new company and proposed the same policy there. There is no time to conduct a preliminary study. Find the minimum sample size required if the CEO wishes to be accurate within (5 + of the true proportion with a confidence of 90.7%. (4 marks)