An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 200 engines and the mean pressure was 7.8 pounds/square inch (psi). Assume the population variance is 1.00. The engineer designed the valve such that it would produce a mean pressure of 7.9 psi. It is believed that the valve does not perform to the specifications. A level of significance of 0.1 will be used. Find the value of the test statistic. Round your answer to two decimal places.
Solution:
Given that,
= 7.9
= 7.8
2
= 100
= 10
n = 200
The Test statistic z is,
= (
-
)
/ (
/
n)
=( 7.8 - 7.9 ) / (10 /
200 )
= ( - 0.1 *
200 /10 )
= (- 0.1*
200 ) / 10
= - 0.45
Test statistic = - 0.45
Get Answers For Free
Most questions answered within 1 hours.