The piston diameter of a certain handpump is 04 inch The manager determines that the diameters are normally distributed, with a mean of 0.4 inch and a standard deviation of 0003 inciv After recalibrating the production machine, the manager randomly selects 26 pistons and determines that the standard deviation is 0.0021 inch. Is there significant evidence for the manager fry conclude that the standard deviation has decreased at the u = 0.10 level of significance? What are the correct hypotheses for this test? The null hypothesis is Hc The altemative hypothesis is HI Help Me Solve This View an Example Get More Help Clear All Check Answer