Answer Happy

Question B3 A health study reported in 2010 that 20% of adults were smokers. A researcher randomly selected 400 adults in 2018 and interviewed to see if these adults were smokers or not. (a) Would the sampling distribution of sample proportion be approximated by a normal (2 marks) distribution? Show your calculation briefly. (b) What is the probability that the proportion of adult smokers in the sample would exceed 25%? (2 marks) Correct the final answer to 4 decimal places. (c) If 76 of those interviewed adults were found to be smokers. By using 0.05 level of significance and critical value approach, test the researcher's claim that the true proportion of adult smokers has changed from the value reported by the health study. Correct the test (8 marks) statistic to 1 decimal place. (d) Explain in the context of the above scenario the meaning of Type I error for the test in part (c). (2 marks)