The piston diameter of a certain hand pump is 0 6 inch The manager determines that the diameters are normally distributed with a mean of 0 6 inch and a standard deviation of 0 005 inch After recalibrating the production machine the manager randomly selects 23 pistons and determines that the standard deviation is 0 0043 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 Ho The alternative hypothesis is H Calculate the value of the test statistic x Round to three decimal places as needed Use technology to determine the P value for the test statistic The P value is Round to three decimal places as needed What is the correct conclusion at the a 0 05 level of significance Since the P value is than the level of significance the null hypothesis There evidence to conclude that the standard deviation has decreased at the 0 05 level of significance sufficient