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 7.5 pounds/square inch (psi). Assume the population standard deviation is 0.9. If the valve was designed to produce a mean pressure of 7.7 psi, is there sufficient evidence at the 0.05 level that the valve does not perform to the specifications? Step 2 of 6: Find the value of the test statistic, Round your answer to two decimal places. Answer Tables Keypad How to enter your answer (opens in new window) Keyboard Shortcuts Previous step answers