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 = 23.50mpg and a standard deviation of = 2.50mpg.

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

Standard error ofX

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(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 [ ]