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 μ = 26.50 mpg and a standard...

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 ofμ = 26.50mpg and a standard deviation ofσ = 3.25 mpg.


(a) What is the standard error of X¯¯¯X¯ , the mean from a random sample of 25 fill-ups by one driver?(Round your answer to 4 decimal places.)


Standard error of   X¯¯¯X¯


(b) Within what interval would you expect the sample mean to fall, with 98 percent probability?(Round your answers to 4 decimal places.)


The interval is from  to