An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 7.4 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 13 engines and the mean pressure was 7.8 pounds/square inch with a standard deviation of 0.7. A level of significance of 0.1 will be used. Assume the population distribution is approximately normal. Find the value of the test statistic. Round your answer to three decimal places.