Using college students as the market segment, describe the most relevant reference group(s) and indicate the probable degree of influence on decisions for each of the following:  a) Brand of toothpaste: friends, roommates = Low  b) Purchase of hybrid car: co-workers, friends = High  c) Purchase of breakfast cereal: family, roommates = Low (if for own use) to High (if group use)  d) Becoming a vegetarian: roommates, friends, family = Moderate