The sample mean is 17,053 divided by 18 equals 947.4. 947.4 minus 1.96 times 188 divided by square root of 18 to 947.4 plus 1.96 times 188 divided by square root of 18.
(a) Determine a 90% confidence interval for population mean
(b) why is the confidence interval you found in part (a) shorter than 860.5 to 1034.3?
(c) Skech a graph
(d) Which confidence interval yields a more precise estimate of the population mean? Explain your answer.