A researcher compares two compounds (1 and 2) used in the manufacture of car tires that are designed to reduce braking distances for SUVs equipped with the tires.
The mean braking distance for SUVs equipped with tires made with compound 1 is 72 feet, with a population standard deviation of 10.6. The mean braking distance for
SUVs equipped with tires made with compound 2 is 74 feet, with a population standard deviation of 12.3. Suppose that a sample of 38 braking tests are performed for
each compound. Using these results, test the claim that the braking distance for SUVs equipped with tires using compound 1 is shorter than the braking distance when
compound 2 is used. Let μ, be the true mean braking distance corresponding to compound 1 and 2 be the true mean braking distance corresponding to compound 2.
Use the 0.05 level of significance.
Step 2 of 5: Compute the value of the test statistic. Round your answer to two decimal places.