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 = 20.25 mpg and a standard deviation of = 2.25 mpg. Within what interval would you expect the sample mean to fall, with 90 percent probability? The sample size is 16 fill-ups by one driver