A consumer agency wants to determine which of two laundry detergents, A or B, cleans better. Fifty pieces of fabric are subjecte
d to the same kinds of stains (grass, mud, coffee). Then 25 pieces are randomly assigned to be cleaned with detergent A, and the remaining 25 pieces are cleaned with detergent B. After being laundered, the pieces of fabric are rated on a scale of 1–10, with 1 being the least clean to 10 being the most clean. The mean rating for detergent A is found to be significantly less than the mean rating for detergent B.
If A has a lower number on the 1-10 scale, that means on average it was closer to the lower end, or the least clean end. This means that A cleans worse than B., and B is better.
