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.

Answer 1

The test statistics is
`t = 1.610`

Explanation:

From the question we are told that

The sample size is n = 210

The sample mean is
`\= x = 5.0 \ pounds /square \ inch`

The standard deviation is
`\sigma = 0.9 \`

The population mean is
`\mu = 4.9 \ psi`

Generally the test statistics is mathematically evaluated as

`t = (\= x - \mu)/( (\sigma )/( √(n) ) )`

=>
`t = (5 - 4.9)/( ( 0.9 )/( √( 210 ) ) )`

=>
`t = 1.610`