SOLUTION: 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=22.25 mpg and

Algebra ->  Probability-and-statistics -> SOLUTION: 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=22.25 mpg and       Log On


   

Question 1197180: 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=22.25 mpg and a standard deviation of σ=1.50 mgp.
a) What is the standard error of X (with a line on top), the mean form a random sample of 36 fill-ups by one driver? (Round your answer to 4 decimal places.)
b) Within what interval would you expect the sample mean to fall, with 99 percent probability? (Round your answer to 4 decimal places.)
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi  
n = 36      µ = 22.25 and σ = 1.50  
a) SE+=+sigma%2Fsqrt%28n%29
SE = 1.50 / √36 =    1.5/6 = .25
b) Within what interval would you expect the sample mean to fall, 
with 99 percent probability? 
ME+=+z%2Asigma%2Fsqrt%28n%29  Interval is  22.25 ± ME
99% confience interval:  z = 2.576
 ME = 2.576(.25) = 1.394
22.25 -1.394< mu < 22.25 + 1.394
 CI(20.856, 23.644)
Wish You the Best in your Studies.