Question 1

Consider a population with the known standard deviation of 19.7. In order to compute a confidence interval for the population mean, a random sample of 144 observations is drawn. (a) Can the sampling distribution of 5: be considered approximately normal? Select an answer a 0' (b) Find the positive value of z; for each of the following confidence levels used in estimating the population mean. Hint: In case of 98% you can use the table of most common z; -values. 36%: a = C] 21% = Selectan answer a o\" 1.48 2 (c) Using the results of part (b) compute the margin of errors at the following confidence levels. Round the answer to 3 decimal places. (d) Which of the two margins of error will result in a wider confidence interval? The width of a confidence interval does not depend on the margin of error. The larger margin of error corresponding to the lower level of confidence results in the wider confidence interval. " ' The smaller margin of error corresponding to the lower level of confidence results in the wider confidence interval. The smaller margin of error corresponding to the higher level of confidence results in the wider confidence interval. The larger margin of error corresponding to the higher level of confidence results in the wider confidence interval