Suppose we are sampling from a normally distributed population and wish to calculate a confidence interval for the population mean u. Find the margin of error if the sample size is 18, the population standard deviation is 15, and the confidence level is 63.2%. Round your answer to three decimal places, i.e., 0.123 Your Answer: Suppose we draw a random sample of n observations from a normally distributed population, and we wish to construct a confidence interval for the population mean u. Suppose that the population standard deviation o is known. Give the confidence level (in percents) for the interval CI = X 1.21 Round your answer to one decimal place, i.e., 0.1 and write the answer as a number, omit the "%" sign. Your Answer: If the population standard deviation of the lifetimes of television screens is estimated to be 250 hours, how large a sample must we take to be 99% confident that the margin of error in estimating the mean lifetime will not exceed 50 hours? You can assume that lifetime of a tv screen is distributed normally. Round your answer to the nearest integer. Your Answer: Answer