A gasoline manufacturer believes a new additive will result in more miles per gallon. A large number of mileage measurements on the gasoline without the additive have been made by the company under...

A gasoline manufacturer believes a new additive will result in more miles per gallon. A large number of mileage measurements on the gasoline without the additive have been made by the company under rigorously controlled conditions. The results show a mean of 24.7 miles per gallon and a standard deviation of 4.8.

Tests are conducted on a sample of 75 cars using the gasoline plus the additive.

The sample mean equals 26.5 miles per gallon.

a.Let’s assume there is adequate basis for a one-tailed test. What is the directional alternative hypothesis?

b.What is the null hypothesis?

c.What is the conclusion? Use??
= 0.051 tail.