Twо cаtаlysts аre being analyzed tо determine hоw they affect the mean yield of a chemical process. Catalyst 1 is currently used, but catalyst 2 is acceptable. Since catalyst 2 is cheaper, it should be adopted, providing it does not change the process yield. An experiment is run in the pilot plant, and 8 batches are made with each catalyst. Yield is approximately normally distributed. Which statistical test should be used to determine whether the mean process yield is the same for both catalysts?