20. A sample of 220 items turned out (during a given week by a certain process) to have average weight of 2.46 lb and standard deviation of 0.57 lb. During the next week, a different lot of raw material was used, and the average weight of a sample of 205 items turned out that week to be 2.55 lb and the standard deviation was 0.48 lb. Assuming normality and equality of variances, would you conclude from these results that the mean weight of the product had increased significantly at the 5% level of significance during the second week?