The highway fuel economy of a 2016 Lexus RX 350 FWD 6-cylinder 3.5-L automatic 5-speed using premium fuel is a normally distributed random variable with a mean of = 21.00mpg and a standard deviation of = 3.25mpg. (a) What is the standard error of X , the mean from a random sample of 16 fill-ups by one driver? (Round your answer to 4 decimal places.) Standard error of X (b)Within what interval would you expect the sample mean to fall, with 90 percent probability?(Round your answers to 4 decimal places.) The interval is from___to___

In a, the capital X should have a horizontal line above it. It will not copy and paste properly