the regular machines used in a cereal packing plant inserts an average of 15.0 ounces of cereal in a box, with a standard deviation of 0.71 ounces. the plant will switch to a newer model of the machine if it reduces the standard deviation further, thereby packing a more consistent product. a test of 25 machines filled by the newer machine indicates a standard deviation of 0.67 ounces. should the plant replace the regular machines with the new? test at the 0.10 significance level.