Question

an engineer has designed a valve that will regulate water pressure on an automobile engine. the valve was tested on 180 engines and the mean pressure was 5.4 pounds/square inch (psi). assume the population standard deviation is 0.9. if the valve was designed to produce a mean pressure of 5.2 psi, is there sufficient evidence at the 0.05 level that the valve performs above the specifications? step 3 of 6: specify if the test is one - tailed or two - tailed. answer 1 point tables keypad keyboard shortcuts

Explanation:

Step1: Identify the claim

The claim is that the valve performs above the specifications (mean pressure > 5.2 psi).

Step2: Determine the type of test

When the alternative hypothesis is of the form $H_1:\mu > \mu_0$, it is a one - tailed test. Here the alternative hypothesis is that the mean pressure $\mu>5.2$ (since we want to check if it performs above the specified 5.2 psi).

Answer:

One - tailed