Question 11: Assume that weights of people are normal distributed with mean u Kg and standard deviation 5 Kg. We select a random sample of size 64 persons. We found that the mean of this sample equals 76 Kg. a) If the estimator is used to estimate u, what is the margin error for this replacement if we use 99% confidence level? b) Determine 99% confidence interval for the mean of people weights. c) If the margin error 8 = 1.01 (for 99% confidence level), what is the sample size (n) that should be withdrawn? -5-