Question

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 6.5 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 26 engines and the mean pressure was 6.6 pounds/square inch with a standard deviation of 1.0. A level of significance of 0.01 will be used. Assume the population distribution is approximately normal. Find the value of the test statistic. Round your answer to three decimal places.

Answer 1

Hypothesis test:

H₀ : = 6.5 (Null Hypothesis)

H₁ :    6.5 (Alternate Hypothesis also called H₁ )

This is two tailed test.

= 6.6

= 6.5

= 1.0

n = 26

Significance level, = 0.01

Test statistic z = = ( - ) / / n

= (6.6 - 6.5)/(1.0/26)

=0.5099 ~ 0.510

Test statistic = 0.510