Doreen thinks that her brother, darren, got more sandwich than she did because their father cut darren’s sandwich into quarters, while hers was left in one piece. doreen’s reasoning is typical of a child in the stage of cognitive development.

Chen's research team randomly assigned some newborns and their mothers either to a breastfeeding promotion group (where breastfeeding was encouraged, but not required) or to a normal pediatric care group (where breastfeeding was neither encouraged nor discouraged). which research method did they use?