Question

An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 210 engines and the mean pressure was 5.0 pounds/square inch (psi). Assume the population standard deviation is 0.9. The engineer designed the valve such that it would produce a mean pressure of 4.9 psi. It is believed that the valve does not perform to the specifications. A level of significance of 0.02 will be used. Find the value of the test statistic. Round your answer to two decimal places.

Answer 1

Solution :

Given that,

= 4.9

= 0.9

n = 210 and

= 5.0

So,  

Z = ( - ) / / n = (5.0 - 4.9) / 0.9 / 210 = 1.61

The value of test statistic = 1.61