A company would like to estimate the effectiveness of two dish detergents using cleanliness ratings. Fifty dirty dishes are randomly selected and randomly divided into two groups. In one group, each dirty dish will be placed in a container of hot water with Brand cap A detergent and in the other group, each dirty dish will be placed in a container of hot water with Brand cap b detergent. The dishes will sit for two hours, and then the cleanliness of the dishes will be measured using a scale of 1 – 10 ( 1 is equal to the least clean and 10 is equal to most clean). The difference in mean cleanliness ratings for the two detergents open paren cap A minus cap b close paren will then be calculated. What is the appropriate inference procedure?