A forester with the National Park Service was tasked with estimating the average age of the bald cypress trees (Taxodium distichum) in Big Cypress Swamp - a region in Everglades National Park. The forester extracted core samples from 40 randomly selected bald cypress trees in Big Cypress Swamp. The mean age of the sample was 274.3 years with a standard deviation of 26.1 years. Using a 90% confidence level, determine the margin of error, E, and a confidence interval for the average age of all bald cypress trees in Big Cypress Swamp. Report the confidence interval using interval notation. Round solutions to two decimal places, if necessary. The margin of error is given by E= A 90% confidence interval is given by