In analyzing the city and highway fuel efficiencies of many cars and trucks, the mean difference in fuel efficiencies for the 601 vehicles was 7.38 mpg with a standard
deviation of 2.51 mpg. Find a 95% confidence interval for this difference and interpret it in context.
The 95% confidence interval for the difference in fuel efficiencies is?
(Round to two decimal places as needed.)

For this case the confidence interval is given by :

Step-by-step explanation:

Data provided

represent the sample mean for the fuel efficiencies

population mean

s=2.51 represent the sample standard deviation

n=601 represent the sample size  

Confidence interval

The formula for the confidence interval of the true mean is given by:

  (1)

The degrees of freedom for this case is given by:

The Confidence level for this case is 0.95 or 95%, and the significance level and and the critical value is given by

Replcing into the formula for the confidence interval is given by:

For this case the confidence interval is given by :