An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 290 engines and the mean pressure was 4.1 pounds/square inch (psi). Assume the population standard deviation is 0.6. The engineer designed the valve such that it would produce a mean pressure of 4.2 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 P-value of the test statistic. Round your answer to four decimal places.

P-value = 0.0046  

Step-by-step explanation:

Given that:

Sample size n = 290

sample mean = 4.1

standard deviation = 0.6

population mean = 4.2

The null and the alternative hypothesis

This is a two-tailed test.

The test statistics can be computed as:

Z = -2.838

P-value = P(Z> 2.838)

P-value = P(Z< -2.838) +P(Z > 2.838)

P-value = 0.00227 + (1 - 0.9977)

P-value = 0.00457

P-value = 0.0046      (to 4 decimal places)

from the figure we get,

the x axis shows   the months and,

the y-axis shows the number of satisfied customer.

each line or each cell in upward direction (y-axis) shows 500.

the appropriate scale for the y - axis is: -

a = 2000 customers

b = 4000 customers

c = 6000 customers

d = 8000 customers

e = 10000 customers

f = 12000 customers

g = 14000 customers