The piston diameter of a certain hand pump is 0.7 inch. The manager determines that the diameters are normally distributed, with a mean of 0.7 inch and a standard deviation of 0.005 inch. After recalibrating the production machine, the manager randomly selects 28 pistons and determines that the standard deviation is 0.0044 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 H0: p OR o OR u less than OR does not equal OR equals OR greater than 0.005 OR 0.0044

The alternative hypthosis is H1: (Choose one of the above choices)

Calculate the value of the test statistic.

Xsquared = (Round to three decimal places as needed).

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 less OR greater than the level of significance, reject OR do not reject the null hypothesis. There is OR is not sufficient evidence to conclude that the standard deviation has decreased at the 0.05 level of significance.