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Comparison of means and confidence interval

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FedEx and United Parcel Service (UPS) are the world's two leading cargo carriers by volume and revenue. According to the Airports Council International, the Memphis International Airport (FedEx) and the Louisville International Airport (UPS) are two of the ten largest cargo airports in the world. The following random samples (in the attached Cargo file) show the tons of cargo per day handled by these airports. Data are in thousands of tons.

a. Compute the sample mean and sample standard deviation for each airport.

b. What is the point estimate of the difference between the two population means? Interpret this value in terms of the higher-volume airport and a comparison of the volume difference between the two airports.

c. Develop a 95% confidence interval of the difference between the daily population means for the two airports.

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This solution is a comparison involving means and show how to find a confidence interval for the difference between two means.

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