The piston diameter of a certain hand pump is 0.4 inch. The manager determines that the diameters are normally distributed, with a mean of 0.4 inch and a standard deviation of 0.007 inch. After...

Extracted text: The piston diameter of a certain hand pump is 0.4 inch. The manager determines that the diameters are normally distributed, with a mean of 0.4 inch and a standard deviation of 0.007 inch. After recalibrating the production machine, the manager randomly selects 29 pistons and determines that the standard deviation is 0.0051 inch. Is there significant evidence for the manager to conclude that the standard deviation has decreased at the a= 0.05 level of significance? .... What are the correct hypotheses for this test? The null hypothesis is H,: 0.007. The alternative hypothesis is H,: 0.007. Calculate the value of the test statistic. x2 =(Round to three decimal places as needed.)