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 = 20.50 mpg and a standard deviation of σ = 3.00 mpg. (a) what is the standard error of x¯¯¯x¯ , the mean from a random sample of 36 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 99 percent probability? (round your answers to 4 decimal places.) the interval is from to

a) Standard error = 0.5

b) 99% Confidence interval:  (19.2125,21.7875)

Step-by-step explanation:

We are given the following in the question:

Population mean =  20.50 mpg

Sample standard deviation = 3.00 mpg

Sample size , n = 36

Standard Error =

99% Confidence interval:

Putting the values, we get,

an advantage of the standard deviation is that it increases as the dispersion of the data increases. e. the interquartile range is preferred when the data are not skewed or no have outliers. an advantage of the standard deviation is that it uses all the observations in its computation.